JP2987013B2 - Exhaust gas purification equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for purifying automobile exhaust gas.

[0002]

2. Description of the Related Art Conventionally, there is an exhaust gas purifying apparatus for purifying exhaust gas of an automobile, in which a catalyst is provided inside a muffler to which exhaust gas is guided. In order for this catalyst to work, a certain temperature (for example, 350 to 400 ° C.) is required, but at the time of starting the vehicle, the catalyst has not yet been sufficiently warmed and harmful components such as CO, soot, HC, and NOx There is a risk of exhausting exhaust gas containing a large amount of.

[0003] In order to avoid this, there has been a method in which a heating wire for heating the catalyst to a temperature at which the purification performance is exhibited is provided, and the catalyst is heated by energizing at the time of a cold start of the vehicle. (JP-A-03-31510). However, there has been a problem that it is difficult to uniformly heat the catalyst with the heating wire, and that the heating time is too long.

In order to solve this problem, a microwave heating device is considered to be effective, and if it is used, uniform and rapid heating is possible. That is, at the time of cold start of the vehicle, the time required to reach the purification performance temperature can be shortened, and the entire catalyst can be uniformly heated, which is very effective in purifying harmful components.

[0005] However, although the microwave heating device can generally perform uniform heating as compared with the heating wire, the heating state depends on the microwave irradiation method, the size and shape of the object to be heated, and the like. Therefore, there is a disadvantage that it is very difficult to set the optimum uniform heating.

[0006] In order to solve this drawback, in a microwave oven for home use, which is a kind of microwave heating device,
A so-called stallafan is installed so that more uniform heating can be performed. The stellar fan is a metal rotator that can diffuse microwaves by rotation, and performs uniform heating by the diffusion. In addition, instead of installing a stellar fan, the object to be heated is rotated.

[0007]

However, installing a stirrer fan provided in a home microwave oven or the like,
In order to rotate the object to be heated, a motor must be provided to perform these rotations. Therefore, the size of the exhaust gas purifying apparatus is increased, which leads to an increase in power consumption and a burden on the vehicle-mounted battery.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an exhaust gas purifying apparatus capable of heating a catalyst more uniformly without increasing the size of the apparatus and imposing a burden on a vehicle-mounted battery. The purpose is to:

[0009]

In order to achieve the above object, the present invention provides an electromagnetic wave absorbing heating element which absorbs electromagnetic waves from an electromagnetic wave oscillator and generates heat, and purifies the heat by the heat of the electromagnetic wave absorbing heating element. In an exhaust gas purifying device that heats a catalyst to an operating temperature, a stirrer fan that rotates by the flow of exhaust gas is provided inside a cavity of the exhaust gas purifying device, and an electromagnetic wave diffused by the stirrer fan is irradiated to an electromagnetic wave absorbing heating element. It is assumed that.

[0010]

[Function] The stellar fan rotates by the flow of exhaust gas,
Diffuses electromagnetic waves. Therefore, there is no need to provide a motor for rotating the stirrer fan.

[0011]

An embodiment of the present invention will be described below with reference to FIG.

The exhaust gas purifying apparatus 1 of this embodiment is provided in the exhaust pipe 3 of an automobile, and purifies harmful components such as CO, soot, HC and NOx in the exhaust gas by a catalyst.
An electromagnetic wave heating device (microwave heating device) 5 is provided in order to quickly heat the catalyst to a purification performance exhibiting temperature at the time of a cold start of an automobile or the like.

The microwave heating device 5 includes an electromagnetic wave generator (magnetron) 7, an electromagnetic wave waveguide 9, and an electromagnetic wave absorbing heating element (microwave) that absorbs electromagnetic waves (herein referred to as microwaves) from the magnetron 7 and generates heat. Absorption heating element) 11.

The microwave generated by the magnetron 7 is first transmitted through the microwave waveguide 9 to the cavity 15.
Microwave absorption heating element (for example, perovskite type composite oxide)
It is led to 11. The microwave absorbing and heating element 11 absorbs microwaves and generates heat, and the heat heats the catalyst. The catalyst (not shown) is provided with a microwave absorbing heating element 1
1 or carried inside the microwave-absorbing heating element 11.

In the former case, it is the exhaust gas that is directly heated by the microwave absorbing heating element 11, and the catalyst is heated by the heat of the exhaust gas. In the latter, the catalyst is directly heated by the microwave absorbing heating element 11.

At the exit of the microwave waveguide 9, a stirrer fan 13 is provided. The stirrer fan 13 is a metal rotating blade, and is rotatably attached to the inner wall of the cavity 15 of the exhaust gas purifying apparatus 1 via a pin 14, and a part of the blade receives the flow of the exhaust gas and rotates.

The stirrer fan 13 is positioned so that a part of the blade covers the vicinity of the exit of the microwave waveguide 9, and reflects and diffuses the microwave guided through the microwave waveguide 9.

The operation of this embodiment will be described below.

At the start of the automobile, the magnetron 7 is energized to generate microwaves. At the same time, the exhaust gas flows through the exhaust pipe 3 when the engine is started.

The exhaust gas flow causes the stirrer fan 13 to rotate. The generated microwave is applied to the microwave waveguide 9.
At its outlet, where it is reflected and diffused by the rotating stirrer fan 13. The diffused microwaves are irregularly reflected inside the cavity 15 and uniformly heat the microwave absorbing and heating elements 11 having a honeycomb structure. According to this, the catalyst is uniformly and rapidly heated, and even during a cold start, harmful components in the exhaust gas are effectively purified.

According to the above-described embodiment, the stellar fan 13
Does not need a motor for rotation because it rotates by the flow of exhaust gas. Therefore, no power is consumed for rotation. Further, it is conceivable that particulates or the like are attached to the stellar fan 13 by exhaust gas. However, since the attached portion is irradiated with microwaves,
Particulates and the like can be heated and burned. Therefore, maintenance for attachment of particulates or the like becomes unnecessary.

Microwave absorption heating element 1 by microwave
1 can be uniformly heated, so that the microwaves do not concentrate on one portion and generate uneven heating, and partial thermal deterioration of the microwave-absorbing heating element 11 can be prevented.

Incidentally, the shape and the mounting position of the stirrer fan 13 can be appropriately determined depending on the installation position of the microwave waveguide 9 and the like.

FIG. 2 shows another embodiment.

The microwave-absorbing heating element 21 is not a heating element itself having a honeycomb structure as in the above embodiment, but a heating element supported on a commercially available ceramic honeycomb. According to the configuration of this embodiment, the microwave heating device 25 includes an electromagnetic wave oscillator (magnetron) 27.
, An electromagnetic wave waveguide 29 and a microwave oscillation antenna 31
And an electromagnetic wave absorption heating element (microwave absorption heating element) 21 that absorbs an electromagnetic wave (herein referred to as a microwave) from the magnetron 27 and generates heat.

The microwave generated by the magnetron 27 is first introduced into the cavity 15 through the microwave waveguide 29 and the microwave oscillating antenna 31, and then the microwave absorbing and heating element (for example, a perovskite-type composite oxide) Object) 21. The microwave absorbing and heating element 21 absorbs microwaves to generate heat, and the heat heats the catalyst.

Thus, according to this embodiment, the stirrer fan 33 made of metal rotating blades is provided inside the cavity 15.
The stirrer fan 33 is rotatably attached to the inner wall of the cavity 15 of the exhaust gas purifying apparatus 1 via the pin 14, and a part of the blade receives the flow of the exhaust gas and rotates.

According to this, as long as the exhaust gas flows, the stirrer fan 33 always rotates.
3 reflects and diffuses the microwave introduced into the cavity 15 through the microwave oscillation antenna 31 and the microwave reflected without being absorbed by the microwave absorbing and heating element 21 again. In addition, the catalyst can be heated uniformly.

[0029]

As described above, according to the exhaust gas purifying apparatus of the present invention, since the electromagnetic wave can be diffused by the stirrer fan rotating by the flow of the exhaust gas to uniformly heat the catalyst, a motor for rotating the stirrer fan can be provided. This eliminates the need to increase the size of the device, thereby preventing an increase in the load on the vehicle-mounted battery.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust gas purifying device 5,25 Electromagnetic wave heating device 7,27 Electromagnetic wave oscillator (magnetron) 9,29 Electromagnetic wave waveguide 11,21 Electromagnetic wave absorption heating element 13,33 Stellar fan 15 Cavity

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masafumi Kasaya 3-13-26 Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Zexel Higashimatsuyama Plant (56) References JP-A-5-202738 (JP, A) JP-A-4-203310 (JP, A) JP-A-6-2535 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01N 3/20 B01D 53/94 F01N 3/24

Claims (1)

(57) [Claims] 1. An exhaust gas purifying apparatus, comprising: an electromagnetic wave absorbing and heating element that absorbs electromagnetic waves from an electromagnetic wave oscillator and generates heat, and heats the catalyst to a temperature at which the catalyst exhibits purification performance by the heat of the electromagnetic wave absorbing and heating element. An exhaust gas purifying apparatus comprising: a stirrer fan that is rotated by a flow of exhaust gas in a cavity of the exhaust gas purifying apparatus; and irradiates the electromagnetic wave absorbing and heating element with electromagnetic waves diffused by the stirrer fan.