DE60200979T2 - Exhaust gas cleaner for cleaning engine exhaust gases - Google Patents

Description

BACKGROUND THE INVENTION

1 , Technical area

The The present invention relates to an exhaust gas purifier for removal of solids in exhaust gas expelled from an internal combustion engine.

2. Description of the state of the technique

In an internal combustion engine used in a motor vehicle or the like is installed, it is necessary to use harmful exhaust gas components such as Nitrogen oxides (NOx) and hydrocarbon (HC) contained in the exhaust gas are to eliminate, to improve the exhaust emissions. Especially in the case of a diesel engine, it is important, in addition to nitrogen oxides and Hydrocarbon solids (PM) such as soot and SOF (Soluble Organic Fraction).

Around to meet such requirements In the past, an "exhaust gas purifier for an internal combustion engine "(exhaust gas cleaner for an internal combustion engine), as described in Japanese Patent No. 2722987. The exhaust gas purifier for an internal combustion engine described in the patent comprises a particulate filter for collecting solids in the exhaust gas in one Exhaust pipe line of an internal combustion engine and is equipped with a Equipped absorbent, which absorbs NOx in the exhaust gas, if an air-fuel ratio of the Exhaust gas is lean, emitting and reducing absorbed NOx, when an oxygen concentration in the exhaust gas is low, and a Absorbent exists which is located in one place where the NOx absorbent Heat too and transfer from the particulate filter.

at such configuration causes the exhaust gas cleaner for an internal combustion engine, that the temperature of the particulate filter increases, using the heat which is generated when a reducing agent on the NOx absorbent burns to thereby collect the solids collected in the particulate filter to burn and remove.

On the other hand, When a particulate filter is used, an exhaust passage in the Particulate filter by concentration of a compound called ash blocked, so that a pressure drop of the exhaust gas increases.

Even though a mechanism for the production of ashes is not yet clarified, It is assumed that various additives and impurities, those in gasoline and lubricating oil an internal combustion engine are contained in a combustion chamber of the internal combustion engine or on the particulate filter to thereby different Form compounds that concentrate on the particulate filter, to form ashes.

To the Examples are components such as sulfur (S), phosphorus (P), calcite (Ca) and magnesium (Mg) contained in the gasoline and lubricating oil of an internal combustion engine, and components contained in blow-by gas and components, in the air-fuel mixture are contained, join in a combustion chamber, making connections such as calcium sulfate (CaSO4), calcium phosphate (Ca3PO4) 2) and magnesium sulfate (MgSO4) are formed together with solids on a particle filter be collected to concentrate ash.

Further, since sulfur (S) possesses the property, easily absorbed by soot to become, combines absorbed in a particulate filter sulfur (S) together with soot with Calcium (Ca) and magnesium (Mg) in the exhaust gas, making connections like Calcium sulfate (CaSO4) and magnesium sulfate (MgSO4) are formed, which accumulate as ashes.

To solve this problem, the EP 1 064 984 A2 (JP-2001-12229) an exhaust gas purifier for an internal combustion engine having a collecting material for collecting solids, wherein the collecting material is charged with a metal having an electronegativity equal to or lower than that of a predetermined component contained in the gasoline and / or or lubricating oil of an internal combustion engine is included.

On This way, the collecting material with the metal with the same high or lower electronegativity, preferably a metal with an electronegativity, which is lower than that of the predetermined component and has a strong ionization tendency, as a predetermined, in the lubricating oil loaded component loaded. It follows that the formation of the Ash is suppressed, because a component that is to be connected, rather with the Metal as connecting to the predetermined component.

However, it has been found that it is difficult to prevent clogging of a particulate filter by calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) as an ash component even when the collecting material is used.

This is because, although phosphorus P and sulfur S do not normally combine with each other, calcium Ca, which most easily binds to phosphorus P, is contained as calcium sulfate (CaSO ₄ ) as described above, resulting in phosphorus P and sulfur S accumulate in the particulate filter, so that they are collected in it. Then, a blockage of the particulate filter by calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) occurs.

In particular, when a vehicle is continuously running in a region where the temperature of the exhaust gas becomes high, a needle-shaped crystal of calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) is formed on a surface of a particulate filter filled with a noble metal such as platinum (Pt ) and has a catalytic function whereby a space is created between purified matter and the noble metal, and the catalytic function may be reduced by half, or the life of a catalyst may be shortened.

The U.S. Patent 4,934,142 discloses an exhaust gas purifier having a first one Filter for removing particles contained in the exhaust gas and a second filter disposed downstream of the first filter is to remove offensive, fragrance components. The first filter is mentioned to Particles and catalytic toxins such as tar, sulfur and phosphorus to filter, which are contained in the exhaust gas.

Further, the DE 664 371 an exhaust gas purifier in which a flow direction of exhaust gases flowing through an exhaust gas purification filter can be changed.

BRIEF SUMMARY OF THE INVENTION

Starting from the from the EP 1 064 984 A2 known exhaust gas cleaner, it is the object of the present invention to provide an exhaust gas cleaner, which can suppress clogging of the particulate filter by the generation of ash due to calcium phosphate (Ca ₃ (PO ₄ ) ₂ ).

These Task is solved by an exhaust gas cleaner according to claim 1. preferred embodiments are in the dependent claims Are defined.

Of the Exhaust gas cleaner for an internal combustion engine according to the present invention The invention includes a particulate filter comprising a collection material that Collects solids that are in the exhaust gas emitted by the internal combustion engine and an ash filter that absorbs phosphorus (P), the contained in the exhaust gas, and the upstream of the collecting material in an exhaust pipe is included, located between the internal combustion engine and the particulate filter.

In The exhaust gas cleaner constructed as described above collects the collecting material Solids contained in the exhaust gas from the internal combustion engine pushed out becomes. The name of the generic material can here, for example, a ordinary DPF (Diesel Particulate Filter) for collecting solids or a DPF containing a catalytic substance such as a NOx absorbent loaded.

Furthermore it's probably that originally in gasoline and / or lubricating oil components contained in the exhaust gas exist. Therefore, there is a possibility that a given component of these components with a further component on the collecting material connects (hereinafter as connected component), so that ash is formed. However, the formation of ashes by the collecting material, the downstream of the ash filter is restricted when the ash filter is upstream of the Collective material is arranged, since the phosphorus (P) of the ash filter is absorbed.

This ash filter can be loaded with a base metal with strong ionization tendency. In this way, it becomes possible to continuously absorb phosphorus (P) in the form of calcium phosphate (Ca ₃ (PO ₄ ) ₂ ).

The term base metal here means a metal with an electronegativity such as that of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra) and lanthanum (La), preferably a metal having an electronegativity lower than that of the predetermined component, and having a strong ionization tendency has. As phosphos continuously combines with these metals, the formation of ashes by calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) in the collecting material downstream of the ash filter is suppressed.

Furthermore it is advantageous to load the collecting material with a metal, that's an electronegativity owns the same size or smaller than that of a predetermined component which is in the Gasoline or in the lubricating oil the internal combustion engine is included. In this way it is possible the Enrichment on the collection material as an ash restrict, which from a compound such as calcium sulfate (CaSO4) and magnesium sulfate (MgSO4) consists of sulfur (S) with calcium (Ca) and magnesium (Mg) is connected in the exhaust.

Further, it is advantageous to select the metal to be loaded so that these compounds under the same conditions as the cleaning conditions split and removed from solids.

In addition, the ash filter can be equipped with an oxidation function. When the oxidation function is present, it becomes easy to filter phosphorus because the accumulation of calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) formed by linking phosphorus and calcium together is facilitated.

According to the present invention, in order to prevent phosphorus contained in the exhaust gases from combining with calcium and accumulating on a collecting material to form ashes, one with a base metal having electronegativity facilitates the combination of the metal with phosphorus would provide charged ash filter in a preliminary stage of this bulk material so that phosphorus is absorbed by this ash filter. Therefore, it is possible to suppress the formation of ashes by calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) in the collecting material.

Further Objects and advantages of the present invention will become apparent from the following Description in conjunction with the accompanying drawings, in which like reference numerals designate the same or similar Designate parts in all figures.

SHORT DESCRIPTION THE DRAWINGS

In the attached Drawings is:

1 a schematic configuration of an internal combustion engine to which an exhaust gas cleaner according to the present invention is attached;

2 an exhaust gas cleaner to which a particulate filter is attached;

3A an image view showing a state in which particles deposit or precipitate on a filter base material;

3B an image view showing a state in which particles are agitated by forward flow and reverse flow of exhaust gases;

4A a front view of a particulate filter;

4B a side view of the particulate filter; and

5A and 5B a conceptual view of an oxidation effect of particles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

in the The following is an exhaust gas cleaner according to the present invention described with reference to the drawings. In this description is an embodiment described in which the exhaust gas cleaner according to the present invention on a diesel engine for a vehicle is applied.

Referring to 1 , reference numeral 1 a motor main body, 2 denotes a cylinder block, 3 denotes a cylinder head, 4 denotes a piston, 5 denotes a combustion chamber, 6 denotes an electrically controlled injection valve, 7 denotes an inlet valve, 8th denotes a suction channel, 9 denotes an exhaust valve and 10 denotes an outlet channel. The intake channel 8th is via a Ansaugabzweigleitung 11 with a collection container 12 coupled, and the collection container 12 is via a suction line 13 with a compressor 15 an exhaust gas turbocharger 14 connected. A Dros selventil 17 that of a stepper motor 16 is operated, is in the intake pipe 13 arranged, and a cooling device 18 for cooling the intake air in the intake pipe 13 is flowing around the intake pipe 13 arranged around. In the in 1 shown example, engine cooling water in the cooling device 18 guided, and the intake air is cooled by the engine cooling water.

On the other hand, the outlet channel 10 via an exhaust manifold 19 and an exhaust pipe 20 with an exhaust gas turbine 21 the exhaust gas turbocharger 14 connected. The discharge opening of the exhaust gas turbine 21 is coupled with an exhaust gas cleaner, which is a housing 23 in which a particulate filter 22 is included.

The exhaust manifold 19 and the collection container 12 are via an exhaust gas recirculation (hereinafter referred to as EGR) - line route 24 interconnected and an electrically controlled EGR control valve 25 is in the EGR pipe line 24 arranged. In addition, a cooling device 26 for cooling an EGR gas in the EGR line 24 flows to the EGR line 24 arranged around. In the in 1 shown example, the engine cooling water is in the cooling device 26 passed, and the EGR gas is cooled by the engine cooling water.

On the other hand, every injector is 6 via a fuel supply line 6a with a fuel reservoir, a so-called common rail 27 , connected. The common rail 27 is powered by an electrically controlled fuel pump 28 , which can change a flow rate, fuel supplied. The the common rail 27 fuel is supplied via each fuel supply line 6a the injection valve 6 fed. A fuel pressure sensor 29 for detecting a fuel pressure in the Com mon rail 27 is on the common rail 27 appropriate. One from the fuel pump 28 amount of fuel delivered is based on an output signals of the fuel pressure sensor 29 so regulated that the fuel pressure in the common rail 27 reaches a desired fuel pressure.

An electronic control unit 30 consists of a digital computer and consists of a ROM (read-only memory) 32 , a RAM (Random Access Memory) 33 , a CPU (processor) 34 , an input interface 35 and an output interface 36 passing through a bidirectional bus 31 connected to each other. An output signal of the fuel pressure sensor 29 is via a corresponding AD converter 37 the input interface 35 fed. In addition, a floor temperature sensor 39 for detecting a bottom temperature of the particulate filter 22 at the particle filter 22 appropriate. An output signal from the soil temperature sensor 39 is via the corresponding AD converter 37 the input interface 35 fed.

In addition, a load sensor 41 for generating an output voltage proportional to a step value L on an accelerator pedal 40 is, with the gas pedal 40 connected, and an output voltage of the load sensor 41 is about the corresponding converter 37 the input interface 35 fed. In addition, a crankshaft sensor 42 with the input interface 35 connected to produce an output pulse each time a crankshaft rotates 30 degrees, for example. On the other hand, the output interface 36 via a corresponding control circuit 38 with the injector 6 , the stepper motor 16 for controlling the throttle valve, the EGS control valve 25 , the fuel pump 28 and an actor 72 , which is described below.

Construction of the exhaust gas cleaner

As in 1 and 2 is shown in the exhaust gas cleaner is an exhaust pipe 70 with the outflow opening of the exhaust gas turbine 21 connected. The exhaust gas purifier comprises a first exhaust gas line section 76 and a second exhaust pipe route 77 coming from the exhaust pipe 70 Branch off to one side or the other side of the filter 22 in the case 23 Being connected, which is the particle filter 22 receives. In addition, the exhaust gas purifier is with a bypass pipe line 73 for direct exhaust of exhaust gases, without the exhaust gases from the branch point of the first exhaust pipe section 76 and the second exhaust pipe route 77 through the particle filter 22 to lead.

In addition, there is an exhaust switching valve 71 in the branch point of the first exhaust pipe section 76 and the second exhaust pipe route 77 arranged. The exhaust switching valve 71 is through the actor 72 actuates and alternately switches between a first flow (forward flow) at which the first exhaust gas line 76 is selected to exhaust from one side of the filter 22 to flow, and a second flow (return flow), in which the second exhaust pipe section 77 is selected to exhaust from the other side of the filter 22 to pour.

In addition, ash filters 80 and 81 the particle filter 22 in the first exhaust pipe line 76 or the second exhaust pipe section 77 upstream. The ash filter 80 and 81 are loaded with base metal having a strong ionization tendency, and phosphorus (P) present in the exhaust gases is absorbed by the base metal.

The Base metal in this context includes, for example, either lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), Francium (Fr), Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), Radium (Ra) or lanthanum (La) or a combination of two or several of these elements.

In addition, a fuel supply nozzle 83 as a reductant delivery means for injecting fuel into exhaust gases entering the filter 22 inflow, is in the first exhaust pipe branch 77 arranged. The fuel injector 83 is controlled by a control means operating on the CPU 34 the electronic control unit 30 is stored.

Here is the case 23 for receiving the filter 22 at a position right above the exhaust pipe 70 passing the bypass line 73 forms, arranged. The first exhaust gas line 76 and the second exhaust pipe section 77 coming from the exhaust pipe 70 Branches are with both ends of the housing 23 connected. Moreover, assuming that a passing direction of exhaust gases is a longitudinal direction, in the filter 22 in the case 23 a distance in a width direction perpendicular to the longitudinal direction longer than a distance in the longitudinal direction. With such a configuration, a space for housing the exhaust gas cleaner, which is out of the housing 23 consists of the filter 22 surrounds, be reduced.

On the other hand, the actor becomes 72 so operated that he from a control means 75 is controlled on the CPU 34 the electronic control unit 30 is applied, and is from a control signal from the output interface 36 controlled. In addition, the actor 72 controlled by a negative pressure, which is formed by the operation of the internal combustion engine. The actor 72 sets a valve body in a position for selecting the first exhaust pipe route 76 (Forward flow direction), if it is not applied with a negative pressure, provides the valve body to a neutral position when it is applied with a first negative pressure, and sets the valve body in a position for selecting the second exhaust pipe section 77 (Backflow direction) when it is applied with a second negative pressure, which is greater than the first negative pressure.

When the valve body is in the forward flow direction indicated by a solid line in FIG 2 is indicated, the exhaust switching valve connects 71 the exhaust pipe 70 with the first exhaust pipe route 76 , and at the same time connects the second exhaust pipe section 77 with the bypass line 73 , As a result, the exhaust gases sequentially flow through the exhaust pipe 70 , the first exhaust pipe line 76 , the filter 22 , the second exhaust pipe branch 77 and the bypass line 73 to be released into the environment.

When the valve body is in the return flow direction indicated by a dashed line in FIG 2 is displayed, the exhaust switching valve connects 71 the exhaust pipe 70 with the second exhaust pipe section 77 , and at the same time connects the first exhaust gas line 76 with the bypass line 73 , Therefore, the exhaust gases flow sequentially through the exhaust pipe 70 , the second exhaust pipe branch 77 , the filter 22 , the first exhaust pipe line 76 and the bypass line 73 to be released into the environment.

When the valve body is in the neutral position parallel to the axis of the exhaust pipe 70 is as indicated by a long-short-dashed line in 2 is displayed, the exhaust switching valve connects 71 the exhaust pipe 70 directly with the bypass line 73 , Therefore, the exhaust gases flow from the exhaust pipe 70 to the bypass line, without the filter 22 to pass to be released into the environment.

Switching between the forward flow and the reverse flow is repeated by switching the valve body, whereby particles such as soot in the base material of the filter 22 move around. Thus, the oxidation of the particles is facilitated, and as a result, the purification of the particles can be carried out efficiently.

3A is an image view of the case where exhaust gases are in one direction only through the filter 22 be guided. In this case, since particles only attach to one side of the filter and do not move, particles not only increase the pressure loss of the exhaust gases, but also prevent the removal of the particles.

3B is an image view of the case where exhaust gases pass through the filter in both directions 22 be guided. In this case, particles in the forward flow direction and the reverse flow direction on both sides of the filter 22 be agitated, the particles move on both sides of the filter 22 or the base material, whereby oxidation of the particles can be facilitated by using active sites existing throughout the filter base material and accumulation of the particles on the filter 22 can be further reduced. Thus, an increase in pressure loss can be avoided.

Structure of the ash filter

Although a shape and a construction of each of the ash filter 80 and 81 is not specifically limited, as long as they can collect particles, if possible, ash filters with a large surface area are preferable.

For example, the ash filters 80 and 81 be of the so-called "wall-flow" type which forms a honeycomb structure using a porous substance as the base material and in which, in honeycomb shape, first flow paths having at their upstream open end portions and at their downstream blocked end portions and second flow paths are alternately arranged at their upstream blocked end portions and at their downstream open end portions. The first flow paths become exhaust gas exhaust ducts whose downstream ends are blocked by plugs, and the second flow paths become exhaust gas outflow ducts whose upstream ends are blocked by plugs. These pipe sections are arranged alternately separated by thin separations.

Phosphorus (P) contained in the exhaust gas is contained in the ash filters 80 and 81 absorbed. In practice, phosphorus (P) combines with calcium (Ca) and accumulates in the ash filters 80 and 81 in the form of calcium phosphate (Ca ₃ (PO ₄ ) ₂ ).

Therefore, the formation of ash from calcium phosphate, which is a compound between phosphorus (P) and calcium (Ca), is in the downstream of the ash filter 80 and 81 arranged particulate filter 22 reduced.

Alternatively, the ash filters 80 and 81 upstream of a switching flow path, that is before the exhaust switching valve 71 be arranged. In addition, phosphorus (P) can be double filtered in the exhaust gases, if the ash filter also in front of the exhaust gas turbocharger 14 are arranged. That is, the ash filters are both in a position near an exhaust manifold where the temperature is high and at a position in the first exhaust passage 76 or the second exhaust pipe section 77 available. Since they can absorb phosphorus (P) in respective ranges with an extremely large temperature difference to each other, the filter efficiency is improved.

Structure of the filter

4 shows a construction of the particulate filter 22 , 4A shows a front view of the particulate filter 22 , and 4B shows a side cross-sectional view of the particulate filter 22 , As in 4A and 4B is shown forms the particle filter 22 a honeycomb structure and is of a so-called "wall-flow" type, with a plurality of exhaust gas flow ducts 50 and 51 is provided, which extend parallel to each other. These exhaust flow pipe routes are from exhaust gas inflow pipe runs 50 whose downstream ends are plugged through plugs 52 are blocked, and Abgasauströmungs line routes 51 whose upstream ends are formed by sealing plugs formed. Furthermore, hatched sections in 4A the plugs 53 , Thus, the exhaust gas inflow pipe runs 50 and the exhaust gas outflow pipe lines 51 alternately, through thin separations 54 separated from each other, arranged. With other words, the exhaust gas inflow pipe sections 50 and the exhaust gas outflow pipe lines 51 are arranged so that each exhaust gas inflow line 50 of four exhaust gas outflow pipe lines 51 is surrounded, and each Abgasausströmungs line route 51 is from four exhaust gas inflow pipe runs 50 surround.

The particle filter 22 is formed of a porous material such as cordierite. Consequently, exhaust gases flowing into the exhaust gas inflow pipe lines flow 50 have flowed out, into the adjacent Abgasausströmungs line routes 51 by passing through the separations 54 kick around them as it is in 4B is shown.

In the embodiment according to the present invention, layers of a substrate made of, for example, aluminum are on peripheral wall surfaces of each exhaust gas inflow pipe 50 and each exhaust outflow conduit 51 that is, on both sides of each separation 54 and on inner wall surfaces of pores of the partition 54 educated. This carrier is provided with a noble metal catalyst and an active oxygen donor / susceptor for containing and holding oxygen when excess oxygen is present and for releasing the retained oxygen in the form of active oxygen when an oxygen concentration around it falls.

platinum (Pt) can be used as the noble metal catalyst. Furthermore can be the active oxygen delivery / pickup be formed of at least one metal which is selected of: an alkali metal such as potassium (K), sodium (Na), lithium (Li), cesium (Cs) and rubidium (Rb), an alkaline earth metal such as barium (Ba), Calcium (Ca) and strontium (Sr), a rare earth metal such as lanthanum (La), yttrium (Y) and a transition metal such as cerium (Ce).

In addition, a valence number of the transition metal (oxygen absorbing agent) such as cerium (Cr) changes depending on the oxygen concentration. Thus, active oxygen is released / absorbed in large quantities by repeatedly changing the oxygen concentration as follows. CeO ₂ (poor) ↔ CeO ₃ (rich)

Furthermore is called active oxygen delivery / pickup preferably an alkali metal or an alkaline earth metal having a higher ionization tendency than that of calcium (Ca) used, that is potassium (K), lithium (Li), cesium (Cs), rubidium (Rb), barium (Ba) and strontium (Sr).

In this embodiment the case is described in which a carrier made of, for example, aluminum or the like with platinum (Pt) as a noble metal catalyst and potassium (K) is loaded as active oxygen donor / transducer.

Continuous oxidation treatment of particles through the filter

Next is a process for removing particles from exhaust gases through the particulate filter 22 described. Moreover, even if other alkali metals, alkaline earth metals, rare earth metals, or transition metals are used as the active oxygen donor / receiver, the particle removing operation is also performed by the same mechanism.

In an internal combustion engine with compression ignition as in 1 is shown, combustion is carried out when an excess of air is present. Therefore, the exhaust gases contain a large amount of excess air. That is, an air-fuel ratio of the exhaust gas is in the compression-ignition engine as shown in FIG 1 shown is high. Because in the combustion chamber 5 Nitrogen monoxide (NO) is generated, further nitrogen monoxide (NO) is contained in the exhaust gases. In addition, sulfur (S) is contained in the fuel, and the sulfur (S) reacts in the fuel chamber 5 with oxygen to sulfur dioxide (SO ₂ ). Consequently, sulfur dioxide (SO ₂ ) is contained in the exhaust gases. Therefore, the exhaust gases containing excess oxygen, nitrogen oxide (NO) and sulfur dioxide (SO ₂ ) flow into the exhaust gas outflow line 50 ,

5A and 5B 12 schematically show enlarged views of the inner circumferential surface of the exhaust gas inflow pipe 50 and a surface of a carrier layer disposed on the inner surface of the pore within the partition 54 is formed. Further referred to in 5A and 5B the reference number 60 Particles of platinum (Pt), and 61 denotes an active oxygen donor / acceptor containing potassium (K).

As described above, when the exhaust gas is accumulated in the exhaust gas inflow pipe section 50 of the particulate filter 22 the oxygen (O ₂ ) on the surface of the platinum (Pt) flows in the form of O ₂ ^- or O ₂ ^- , as it is in 5A is shown because a large amount of excess oxygen is contained in the exhaust gases. On the other hand, nitrogen oxide (NO) in the exhaust gases reacts with the O ₂ ^- or O _2- on the surface of the platinum (Pt) to form nitrogen dioxide (2NO + O ₂ → 2NO ₂ ). Subsequently, a portion of the generated nitrogen dioxide (NO2) in the active oxygen donor / receiver 61 while being oxidized on the platinum (Pt) and diffuses in the active oxygen donor / susceptor 61 in the form of nitric oxide ions (NO ₃ ^- ), as in 5A where it combines with potassium (K). Part of the nitric oxide ions (NO ₃ ^- ) produces potassium nitrate (KNO ₃ ).

On the other hand, as described above, sulfur dioxide (SO ₂ ) is also contained in the exhaust gases, and this sulfur dioxide (SO ₂ ) also becomes in the active oxygen donor / receiver by the same mechanism as that of the absorption of nitrogen dioxide (NO ₂ ) 61 absorbed. That is, oxygen (O ₂ ) deposits on the surface of the platinum (Pt) in the form of O ₂ ^- or O _2- as described above, and the SO ₂ in the exhaust gases reacts with the O ₂ ^- or O ^2- on the surface of the platinum (Pt) to (SO ₃ ).

Subsequently, part of the generated (SO ₃ ) in the active oxygen donor / receiver 61 absorbed; being further oxidized on the platinum (Pt) and diffusing in the active oxygen donor / receiver 61 in the form of sulfate oxide ions (SO ₄ ^2- ), combining with potassium K to form potassium sulfate (K ₂ SO ₄ ). In this way, potassium nitrate (KNO ₃ ) and potassium sulfate (K ₂ SO ₄ ) in the active oxygen donor / receiver 61 educated.

On the other hand, in the combustion chamber 5 Particles consisting essentially of carbon C generated. Therefore, these particles are contained in the exhaust gas. This particle contained in the exhaust gas contacts a surface of a carrier layer, for example the surface of the active oxygen donor / receiver 61 , and divorce, as indicated by the reference number 62 in 5B is shown when the exhaust gases through the exhaust gas inlet pipe line 50 of the particulate filter 22 flow or when the exhaust gases from the exhaust gas inlet line 50 to the exhaust gas outlet line 51 move.

If the particles 62 on the surface of the active oxygen delivery / pickup 61 Depositing in this way sinks on a contact surface between the particle 62 and the active oxygen delivery / pickup 61 the oxygen concentration. As the oxygen concentration thus decreases, occurs between the contact surface and a high oxygen concentration in the active oxygen donor / receiver 61 a concentration difference, whereby oxygen in the active oxygen donor / receiver 61 it tends to become the contact surface between the particle 62 and the active oxygen delivery / pickup 61 to move. As a result, potassium nitrate (KNO ₃ ), which is in the active oxygen donor / acceptor 61 is formed, dissociated in potassium (K) and oxygen (O). The oxygen (O) moves to the contact surface between the particle 62 and the active oxygen delivery / pickup 61 and the nitrogen monoxide (NO) is released to the outside of the active oxygen donor / receiver 61 released. The released nitric oxide (NO) is oxidized on the platinum (Pt), on its downstream side, and again in the active oxygen donor / receiver 61 absorbed.

In addition, it seems that active oxygen is also produced in a reaction process with oxygen and the particle 62 oxidize when oxygen and NOx in the exhaust gases are occluded in an oxygen excess state.

As described above, NO in the exhaust gases reacts with O ₂ ^- or O _2- on the surface of platinum to NO ₂ (2NO + O ₂ → 2NO ₂ ). Subsequently, a part of the produced (NO ₂ ) converts into (NO ₃ ) and becomes in the active oxygen donor / receiver 61 which is oxidized to platinum (Pt).

Part of the NO ₂ is dissociated by a catalyst and releases active oxygen. That is, the NO ₂ repeats the oxidation and the dissociation such that active oxygen is released: 2NO ₂ → NO + O * → NO + O ₂ → NO + O * →.

On the other hand, at this point potassium sulfate (K ₂ SO ₄ ), which is present in the active oxygen donor / on taker 61 is also dissociated in potassium K, oxygen (O) and (SO ₂ ). The oxygen (O) moves to the contact surface between the particle 62 and the active oxygen delivery / pickup 61 and the SO ₂ goes outward from the active oxygen delivery / pickup 61 released. The externally released (SO ₂ ) is oxidized to platinum (Pt) on its downstream side and back into the active oxygen donor / receiver 61 absorbed. However, it is difficult to release active oxygen compared to potassium nitrate (KNO ₃ ) because potassium sulfate (K ₂ SO ₄ ) is stable.

The oxygen (O) that attaches to the contact surface between the particle 62 and the active oxygen delivery / pickup 61 is oxygen, which has split off from compounds such as potassium nitrate (KNO ₃ ) or potassium sulfate (K ₂ SO ₄ ). The oxygen (O) which has split off from a compound has a high energy and high activity. Therefore, the oxygen that has become the contact surface between the particle 62 and the active oxygen delivery / pickup 61 has moved into active oxygen (O). If such an active oxygen (O) is the particle ( 62 ), the particle becomes 62 in a short time (within a few minutes to a few tens of minutes) without the emission of light flames oxidized and disappears completely. Therefore, the particle separates 62 never on the particle filter 22 from.

If particles are attached to the particulate filter 22 deposited in laminated form, burned in a conventional manner, the particle filter glows 22 and burnt accompanied by flames. Such burning accompanied by flames does not last unless high temperatures prevail. Therefore, the temperature of the particulate filter 22 held high to cause the burning accompanied by flames to last.

In contrast, in the present invention, the particle 62 oxidized without emitting flares as described above when the surface of the particulate filter 22 does not glow. That is, in other words, in the present invention, the particle becomes 62 oxidized and removed at a considerably low temperature compared to the prior art. Therefore, a particle removal process differs by oxidation of the particle 62 without emitting luminous flames according to the present invention entirely from a particle removal operation by prior art combustion accompanied by flames.

In addition, the particle removal process is carried out by oxidation of particles at an extremely low temperature. Therefore, the temperature of the particulate filter increases 22 not so high, so that there is almost no danger that the particle filter 22 deteriorated.

As particles hardly on the particle filter 22 Moreover, there is a danger that ashes that are slag from particles will separate. Therefore, the danger is that the particle filter 22 clogged, less.

Incidentally, the clogging is mainly caused by calcium sulfate (CaSO ₄ ). That is, fuel and lubricating oil contain calcium (Ca). Therefore, calcium (Ca) is contained in the exhaust gases. When SO ₃ is present, produces calcium (Ca) of calcium sulfate (CaSO _4). Calcium sulfate (CaSO ₄ ) is stable and does not dissociate thermally, even when heated. Therefore, the clogging is caused when calcium sulfate (CaSO ₄ ) is produced and the pores of the particulate filter 22 blocked by calcium sulfate (CaSO ₄ ).

In this case, however, the active oxygen donor / receiver bonds 61 distributed SO ₃ with potassium (K) to form potassium sulfate (K ₂ SO ₄ ) when an alkali metal or an alkaline earth metal, which has a higher ionization tendency than that of calcium (Ca), for example potassium (K), as the active oxygen -Abgeber / transducers 61 is used. Calcium (Ca) flows through the separations 54 of the particulate filter 22 into the exhaust gas outflow line 51 without connecting to SO ₃ . As a result, the pores of the particulate filter become 22 no longer blocked. Therefore, as described above, as the active oxygen donor / receiver 61 Preferably, an alkali metal or an alkaline earth metal having a higher ionization tendency than that of calcium (Ca) used, that is, potassium (K), lithium (Li), cesium (Cs) or beryllium (Be).

Furthermore, since potassium sulfate (K ₂ SO ₄ ), that instead of ash on the particulate filter 22 having a lower concentration compared to calcium sulfate (CaSO ₄ ), it can be easily dissociated and removed by lowering the ambient temperature of the particulate filter 22 is increased or by the particle filter 22 is brought into a reducing atmosphere.

Incidentally, in practice, it is almost impossible to reduce the amount M of ejected particles in all operating states to be less than an amount G of particles that can be oxidized and removed. For example, the temperature of the particulate filter 22 usually low when starting a machine. Therefore, in this case, the amount of ejected particle M is usually larger than the amount G of particles that can be oxidized and removed. When the amount M of ejected particles is larger than the amount G of Particles that can be oxidized and removed, such as immediately after the engine is started, will start particulates that have not been oxidized at the particulate filter 22 to stick.

In this way, the amount of ejected particle M is increased to be larger than the amount G of particles that can be oxidized and removed, and in some cases, particulates may be formed on the particulate filter 22 in a laminated form.

To the particles that are on the particle filter 22 separating, oxidizing and removing, becomes the switching valve 71 that in the exhaust pipe 70 is arranged, switched. When the switching valve 71 is switched, the side facing the exhaust gas flow direction side and pointing in the exhaust gas flow direction side of the particulate filter 22 vice versa. In a part, before switching the switching valve 71 the exhaust gas flow direction side of the particulate filter 22 was deposit on the surface of the active oxygen donor / acceptor 61 Particles are released, and active oxygen (O) is released, whereby the particles are oxidized and removed. A portion of the released active oxygen O, together with the exhaust gases and oxidized and removed particulates that separate there, moves to the exhaust gas flow direction side of the particulate filter 22 , Here, as described above, the particles in the forward flow direction and the reverse flow direction become both sides of the particulate filter 22 jumbled and moving on both sides of the particle 22 or in the interior of the base material, to encounter activation points throughout the film base material so that they are oxidized.

In this way, particles, if the particles that were not oxidized, on the particle filter 22 deposit, completely oxidized and from the particulate filter 22 are removed by the side pointing in the exhaust gas flow direction side and the side facing the exhaust gas flow direction side of the particulate filter 22 be reversed.

Further, if particles are on the particulate filter 22 The particles are oxidized without luminous flame formation by causing an air-fuel ratio of some or all of the exhaust gas to be temporarily rich. When the air-fuel ratio of the exhaust gas is made rich, that is, when an oxygen concentration in the exhaust gas is decreased, the active oxygen (O) becomes uninterrupted from the active oxygen donor / receiver 61 released to the outside. The particles that are on the particle filter 22 are burned and removed in a short time (within a few minutes to a few tens of minutes) without luminous flame formation.

Further embodiments

Although in the above-mentioned embodiment, a collecting material is described as a material capable of eliminating NO _x and oxidizing particles, it is not limited to the above-mentioned material, and any material may be used as long as it is a filter for collecting solids such as soot and unburned fuel components in the exhaust gases.

Further can be upstream of one Exhaust system a blind converter or the like additionally provided be to thereby filter out phosphorus, taking advantage of the property is that phosphorus tends to be absorbed in one place, where a flow the exhaust gas is disturbed, or in a first element.

Further, although in this embodiment a Diesel engine as an example of an internal combustion engine is described, to which the exhaust gas cleaner according to the present Invention is applied, it is unnecessary to mention that the exhaust gas cleaner can be applied to a gasoline engine.

However, in the case of a gasoline engine, since a sulfur (S) component contained in the fuel is in a smaller amount, a phosphorus (P) component is in a larger amount compared to those in a diesel engine, calcium (Ca) and Phosphorus (P) - component to connect with each other, so that calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) is formed on a particulate filter.

According to the present invention, as described above, an ash filter disposed upstream of the particulate filter is combined with a metal having an electronegativity equal to or smaller than that of calcium (Ca) and a strong ionization tendency (e.g. Potassium (K)), whereby a compound of potassium (K) or the like with the phosphorus (P) component is preferred over a compound of calcium (Ca) with the phosphorus (P) component, so that the formation of (Ca ₃ (PO ₄ ) ₂ ) is suppressed. Therefore, the exhaust gas cleaner according to the present invention is extremely effective for use in a gasoline engine.

The exhaust gas purifier for an internal combustion engine according to the present invention comprises, above a collecting material, an ash filter loaded with a base metal, a component to be joined forming ashes, when formed into a compound having a predetermined component, is preferably bonded to the metal one, compared to the predetermined one Component. Thus, the formation of ashes is suppressed.

Therefore it will be according to the present Invention in the exhaust gas cleaner, with the collecting material for collecting of solids in the exhaust gas is possible, the formation of ashes to suppress, so as to prevent the collecting material from being blocked by ash is, and it can be prevented that a function of the generic material destroyed becomes.

It Thus, it is considered that an exhaust gas cleaner for an internal combustion engine provided. One skilled in the art will recognize that the present invention Invention be carried out by other than the preferred embodiments may, which are presented for purposes of illustration and not limitation are, and the present invention is only by the following claims limited.

Claims (6)

Exhaust gas cleaner for an internal combustion engine ( 1 ), comprising: a particulate filter ( 22 ) comprising a collecting material which collects solids which are in the from the internal combustion engine ( 1 ) are exhausted, and an ash filter ( 80 . 81 ) which absorbs phosphorus (P) contained in the exhaust gas, characterized in that the ash filter ( 80 . 81 ) in a between the internal combustion engine ( 1 ) and the particle filter ( 22 ) extending exhaust pipe ( 20 . 70 . 73 . 76 . 77 ) upstream of the particulate filter ( 22 ) is provided. Exhaust gas cleaner for an internal combustion engine ( 1 ) according to claim 1, wherein the ash filter ( 80 . 81 ) is loaded with a base metal. Exhaust gas cleaner for an internal combustion engine ( 1 ) according to claim 1 or 2, wherein the ash filter ( 80 . 81 ) has an oxidation function. Exhaust gas cleaner for an internal combustion engine ( 1 ) according to one of claims 1 to 3, wherein the collecting material is loaded with a metal which has an electronegativity equal to or lower than the electronegativity of a certain component which is present in the fuel or lubricating oil of the internal combustion engine ( 1 ) is included. Exhaust gas cleaner for an internal combustion engine ( 1 ) according to claim 4, wherein the metal is selected such that a compound of this metal with the particular component is decomposed or eliminated under the same conditions as the purification conditions of the solids. Exhaust gas cleaner for an internal combustion engine ( 1 ) according to claim 1, further comprising: a first exhaust pipe section ( 76 ), which is connected to one side of the collecting material, a second exhaust gas line ( 77 ), which is connected to the other side of the collecting material, and an exhaust manifold ( 71 ) for conducting the exhaust gas selectively into the first exhaust gas line ( 76 ) or in the second exhaust pipe section ( 77 ), the ash filter ( 80 . 81 ) in the first exhaust line section ( 76 ) and in the second exhaust pipe section ( 77 ) is provided.