JPH09317445A - Exhaust emission control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce the discharged amount of NOx in exhaust gas from an exhaust emission control system which injects fluid into exhaust gas to capture products therein, separates the products and re-injects the fluid thus purified through the separation into exhaust gas, by providing a purifying body and an ozone supply means for supplying ozone to exhaust gas in the halfway portion of an exhaust pipe. SOLUTION: When the engine is running, the fluid in a fluid tank 26 is injected from a fluid injection nozzle 34 into exhaust gas to capture products therein. A filter 44 separates the products incorporated in the fluid to purify the fluid, and the purified fluid is re-injected from the fluid injection nozzle 34 into exhaust gas. In recovering products in exhaust gas, the mixture of exhaust gas and fluid flows into a lead pipe 18 through an upstream side exhaust pipe 4-1, and directed from an upstream side port 20 into a swirling means 50 through an ozone mixing chamber which is located in an enclosed body 64 and produces ozone by heating a ceramics body to supply it from an ozone supply means 58. The supplied ozone oxidizes NOx in exhaust gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification system, and more particularly to an exhaust gas purification system that can effectively reduce the amount of NOx emitted from the exhaust gas and can be made compact.

[0002]

2. Description of the Related Art Engines generally include an ignition and combustion type gasoline engine and a self-ignition type diesel engine. The exhaust system of the engine is equipped with a catalyst for purifying the exhaust and a silencer called a "silencer" or a "muffler" for reducing exhaust noise.

The catalyst includes an oxidation catalyst, a reduction catalyst, a three-way catalyst and the like, and in terms of shape, there are a pellet type (granular type), a monolith type (plate type) and the like.

The oxidation catalyst reduces CO (carbon monoxide) and HC (hydrocarbons) in exhaust gas by utilizing an oxidation phenomenon. Further, the reduction catalyst reduces NOx (nitrogen oxide) in the exhaust gas by reduction. The three-way catalyst reduces the three components of CO, HC and NOx in the exhaust gas.

[0005]

By the way, recently, there is a tendency that regulations on exhaust gas discharged from a vehicle, particularly, regulations on exhaust gas discharged from a vehicle equipped with a diesel engine are strengthened. Measures against smokey carbon are being considered.

Therefore, the applicant of the present invention has already applied for an exhaust gas purification system capable of effectively recovering carbon, CO, HC, NOx and other products in the exhaust gas by means of a fluid. This exhaust purification system controls to inject a fluid into the exhaust of an engine so that the product contained in the exhaust is contained in the fluid, and the product contained in this fluid is separated and the purified fluid is injected again into the exhaust. To do.

However, in this exhaust gas purification system, since only the fluid is injected into the exhaust gas, the N in the exhaust gas is exhausted.
Since Ox cannot be sufficiently adhered to the fluid together with other products in the exhaust gas, NOx cannot be contained in the fluid to be efficiently recovered, thus effectively reducing the NOx emission amount. However, there is an inconvenience that it is not possible and the size becomes large.

[0008]

In order to eliminate the above-mentioned inconvenience, therefore, the present invention injects a fluid into the exhaust gas flowing in the exhaust pipe so that the product in the exhaust gas is contained in the fluid, and In an exhaust gas purification system that controls so that a fluid that has separated and purified the contained products is injected again into the exhaust gas, a purification body that forms a purification chamber in the middle of the exhaust pipe, and ozone in the exhaust gas on the upstream side of the purification body And an ozone supply means for supplying.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention oxidizes NOx into nitrogen oxides by supplying ozone from an ozone supply means to exhaust gas, and sufficiently adheres to fluid together with other products in exhaust gas. Then, the NOx is efficiently recovered to effectively reduce the NOx emission amount. Further, by providing the ozone supply means in the middle of the exhaust pipe, the generated ozone is immediately supplied to the exhaust gas to further reduce the NOx emission amount. It is possible to reduce the number and make the exhaust gas purification system compact.

[0010]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. 1 to 4 show an embodiment of the present invention. In FIG. 1, 2 is an exhaust purification system. The exhaust gas purification system 2 is provided in the middle of an exhaust system from an exhaust port (not shown) of an engine (not shown) such as a diesel engine to an exhaust outlet (not shown) of an exhaust passage 6 formed by an exhaust pipe 4.

The exhaust gas purification system 2 has a purification body 8 provided in the middle of the exhaust pipe 4. As a result, the exhaust pipe 4 is separated across the purification body 8 into the upstream exhaust pipe 4-1 and the downstream exhaust pipe 4-2. The purification body 8 is the peripheral wall 1
0 and the upstream and downstream partition walls 12 and 14 at both ends in the longitudinal direction are formed into a hollow cylindrical shape to form a purification chamber 16.

The upstream exhaust pipe 4-1 introduces exhaust gas and a fluid injected into the exhaust gas into the purifying chamber 16 side to introduce a pipe 18.
One end side of is connected. The opening 20 on the other end side of the introduction pipe 18 is provided with an encapsulant 64 of the ozone supply means 58 described later.
It is located inside. As shown in FIG. 2, the introduction pipe 18 is formed with a plurality of exhaust circulation holes 18a.

A discharge pipe 22 for discharging the exhaust gas of the purification chamber 16 to the outside is provided in the downstream partition wall 14 on the other end side in the longitudinal direction of the purification body 8. The outlet pipe 22 is
It has a downstream opening 24 on one end side, an intermediate portion is held by the downstream partition wall 14, and the other end side is connected to the downstream exhaust pipe 4-2.

The exhaust gas purification system 2 is provided with a fluid tank 26 for storing the fluid injected into the exhaust gas. The fluid tank 26 includes a level gauge 2 for detecting the liquid level.
8 and a sensor 30 for detecting a dirty state of the fluid. One end of a fluid supply pipe 32 is connected to the fluid tank 26. This fluid supply pipe 32
The other end of the upstream exhaust pipe 4 upstream of the purification main body 8
-1 is provided so as to communicate with the fluid injection nozzle 34 facing the exhaust passage 6.

A plurality of swirling-side fluid discharge holes 36 are formed in the lower portion of the peripheral wall 10 of the purifying body 8 from the vicinity of the upstream partition 12 to the vicinity of the downstream partition 14. Further, the outer peripheral surface 38 of the peripheral wall 10 in which the swirling-side fluid discharge hole 36 is formed
A swirl-side fluid collecting section 40 that reaches from the upstream side partition wall 12 to the downstream side partition wall 14 is attached and provided in the. One end side of a fluid recovery pipe 42 is provided in communication with the swirling side fluid collecting section 40. The other end of the fluid recovery pipe 42 is connected to the fluid tank 26. A filter 44 is provided in the middle of the fluid recovery pipe 42.
A detachable filter element (not shown) is built in the filter 44.

A fluid pumping section 46 for pumping the fluid to the fluid jet nozzle 34 is provided in the middle of the fluid supply pipe 32. Therefore, the fluid supply pipe 32 is separated into a tank-side fluid supply pipe 32-1 between the fluid tank 26 and the fluid pumping unit 46 and a nozzle-side fluid supply pipe 32-2 between the fluid pumping unit 46 and the fluid injection nozzle 34. To be done. The operation of the fluid pumping unit 46 is controlled by the control unit 48.

In the exhaust gas purification system 2, the control unit 4
The operation of the fluid pumping unit 46 is controlled by 8 to pump the fluid in the fluid tank 26 to the fluid supply pipe 32, and the fluid is ejected from the fluid injection nozzle 34 to the exhaust to produce the product in the exhaust in the atomized fluid. Include.

Further, in the exhaust gas purification system 2, the liquefied fluid containing the product in the exhaust gas is collected from the swirling side fluid discharge hole 36 to the swirling side fluid collecting section 40, and the fluid is collected by the fluid collecting pipe 42. The filter 44 separates and purifies the product contained in the fluid recovered by natural fall into the tank 26, and the fluid pumping unit 46 injects the purified fluid in the fluid tank 26 again to the exhaust gas from the fluid injection nozzle 34. Control. By providing the fluid recovery pipe 42 with a fluid suction unit (not shown) that suctions the fluid toward the fluid tank 26 side, the fluid can be forcibly recovered in addition to the recovery by spontaneous fall.

A swirling means 50 is provided in the purification chamber 16 of the purification body 8. The swirl means 50 has a swirl member 52 in which a hollow cylindrical member is wound in a coil shape in the purification chamber 16 in the purification body 8.

The turning member 52 has a turning passage 54 formed therein. A fluid outlet hole 56 is provided so as to connect the swirl passage 54 and the purification chamber 16 to each other. The fluid outlet hole 56 guides the fluid containing the product in the exhaust gas from the swirling passage 54 to the purification chamber 16 on the outside.

The swirling member 52 has one end opening to the upstream partition 12 of the purification body 8 and the other end penetrating the downstream partition 14 of the purification body 8 and facing the purification chamber 16 downstream of the outlet pipe 22. The downstream side opening 24 of the outlet pipe 22 without connecting to the opening 24
It is located in the vicinity.

An ozone supply means 58 for supplying ozone to the exhaust gas is provided on the upstream side of the purification main body 8 in the middle of the exhaust pipe 4 and on the outer surface of the upstream side partition wall 12 including the introduction pipe 18.

As shown in FIGS. 2 and 3, the ozone supply means 58 has an annular ceramic body 62 which is fitted onto the introduction pipe 18 to form an annular space 60, and an encapsulation which encloses the ceramic body 62. And a body 64. The envelope 64 forms an ozone mixing chamber 66.

One end side of the ceramic body 62 is fixed to the envelope partition wall 68, and is formed, for example, in an annular shape as shown in FIG. 3, and the other end side is open to the ozone mixing chamber 66.
In the ceramic body 62, a plurality of electric wires 70 are embedded at equal intervals in the circumferential direction in the axial direction. By thus embedding the electric wire 70 in the ceramic body 62, an insulating effect and the like can be obtained. A power supply unit 72 that supplies power is connected to the electric wire 70.

The ceramic body 62 is shown in FIG.
It is also possible to form a square ring as shown in FIG.

A plurality of ozone-side fluid discharge holes 74 are formed and provided in the lower portion of the envelope 64. The ozone-side fluid discharge hole 7 is formed on the outer surface 64a of the envelope 64.
Ozone-side fluid collector 7 so as to collect fluid from
6 are provided. The ozone-side fluid collector 76
The swirl side fluid collecting section 40 is communicated with via the communication pipe 78.

Next, the operation of this embodiment will be described.

In the exhaust gas purification system 2, the control unit 4
The operation of the fluid pumping unit 46 is controlled by 8 to pump the fluid in the fluid tank 26 to the fluid supply pipe 32, and the fluid is ejected from the fluid injection nozzle 34 to the exhaust to produce the product in the exhaust in the atomized fluid. Include.

Further, in the exhaust gas purification system 2, the liquefied fluid containing the product in the exhaust gas is collected from the swirling side fluid discharge hole 36 to the swirling side fluid collecting section 40, and the fluid is collected by the fluid collecting pipe 42. The product contained in the fluid collected in the tank 26 is separated and purified by the filter 44, and the fluid that has been purified in the fluid tank 26 is controlled to be jetted again from the fluid jet nozzle 34 to the exhaust by the fluid pumping unit 46.

In the exhaust gas purification system 2, products in the exhaust gas (for example, carbon, CO, HC, NOx, etc.)
At the time of recovery, the mixture of exhaust gas and fluid flows into the introducing pipe 18 from the upstream exhaust pipe 4-1 and is introduced into the swirling means 50 from the upstream opening 20 through the ozone mixing chamber 66 in the envelope 64. To be done.

At this time, in the ozone supply means 58, the ceramic body 62 is heated by supplying power to the electric wire 70 from the power supply section 72, and ozone is generated by the heating of the ceramic body 62. The ozone is supplied to the exhaust gas of the ozone mixing chamber 66 in the envelope 64. This ozone oxidizes NOx in the exhaust gas into nitrogen oxides. This nitrogen oxide is contained in the fluid jetted from the fluid jet nozzle 34 by the centrifugal effect of the swirling means 50 together with other products such as carbon. In addition, the fluid in the ozone mixing chamber 66 is collected from the ozone-side fluid discharge hole 74 to the ozone-side fluid collecting portion 76 and flows out from the communication pipe 78 to the swirling fluid collecting portion 40 side.

The fluid containing nitrogen oxides and other products in the swirling passage 54 is guided to the outer purification chamber 16 from the fluid outlet 56 and discharged to the outside from the swirling fluid discharge hole 36 to swirl fluid. It is collected by the collecting unit 40. The fluid collected in the swirling-side fluid collecting section 40 is purified by separating contained nitrogen oxides and other products by the filter 44, and collected in the fluid tank 26 through the fluid collecting pipe 42.

The purified fluid in the fluid tank 26 is again jetted from the fluid jet nozzle 34 to the exhaust by the fluid pumping unit 46. Further, the exhaust gas from which the nitrogen oxides and other products have been removed flows into the outlet pipe 22 through the downstream opening 24 and is discharged to the outside through the downstream exhaust pipe 4-2.

As described above, the swirling means 50 swirls the exhaust gas and the fluid, and the centrifugal effect of the swirling allows the exhaust gas and the fluid to be well agitated and mixed, and the product in the exhaust gas is made into the fluid by this agitation and mixing. It can be attached and contained.

As a result, the product in the exhaust gas can be contained in the fluid and can be recovered well, and the emission amount of the harmful exhaust gas component can be reduced.

Further, by providing the ozone supply means 58 for supplying ozone to the exhaust gas on the upstream side of the swirling means 50, NOx in the exhaust gas is oxidized to nitrogen oxides, and together with other products in the exhaust gas. It can be contained by being sufficiently attached to a fluid.

As a result, NOx in the exhaust gas can be efficiently contained in the fluid and can be recovered well, and the amount of NOx discharged can be effectively reduced.

Further, since the ozone supply means 58 is provided in the middle of the exhaust pipe 4, the generated ozone is immediately supplied to the exhaust gas to further reduce the NOx emission amount.
Since it is not necessary to separately provide the ozone supply means 58 at another location, the exhaust gas purification system 2 can be made compact.

[0039]

As is apparent from the above detailed description, according to the present invention, there is provided a purification main body forming a purification chamber in the middle of the exhaust pipe and an ozone supply means for supplying ozone to the exhaust gas on the upstream side of the purification main body. By providing the ozone from the ozone supply means to the exhaust gas, NOx is oxidized to nitrogen oxides and sufficiently adhered to the fluid together with other products in the exhaust gas to be contained, thereby improving NOx. Collect and N
It is possible to effectively reduce the emission amount of Ox.

Since the ozone supply means is provided in the middle of the exhaust pipe, the NOx emission amount can be further reduced and the exhaust gas purification system can be made compact.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an exhaust gas purification system.

FIG. 2 is a sectional view of ozone supply means.

FIG. 3 is a front view of an introduction pipe and a ceramic body.

FIG. 4 is a front view of an introduction pipe and a ceramic body having another shape.

[Explanation of symbols]

 2 Exhaust gas purification system 4 Exhaust pipe 6 Exhaust passage 8 Purification body 16 Purification chamber 18 Introducing pipe 22 Outlet pipe 26 Fluid tank 32 Fluid supply pipe 34 Fluid injection nozzle 46 Fluid pressure feeding unit 48 Control unit 50 Swirling means 58 Ozone supplying means 62 Ceramic body 64 Encapsulation 66 Ozone Mixing Room 72 Power Supply Section

Claims (1)

[Claims] 1. A fluid is injected into the exhaust gas flowing through the exhaust pipe so that the product in the exhaust gas is contained in the fluid, and the product contained in the fluid is separated and the purified fluid is injected into the exhaust gas again. In the controlled exhaust purification system,
An exhaust gas purification system characterized in that a purification main body forming a purification chamber and an ozone supply means for supplying ozone to the exhaust gas are provided upstream of the purification main body in the middle of the exhaust pipe.