JPS6143937Y2 - - Google Patents

Description

Detailed Description of the Invention This invention relates to an exhaust purification device that can effectively utilize a catalyst device.

For the purpose of reducing unburned harmful components (HC, CO) in exhaust gas, there is a conventionally known method of installing a catalytic converter in the exhaust system and simultaneously supplying secondary air to oxidize the unburned harmful components. be. By the way, this catalyst is sometimes installed in a high-temperature atmosphere where it is likely to react, that is, in the exhaust manifold upstream of the exhaust system, but if a secondary air introduction pipe is also installed with the tip opening at the exhaust port,
Because the distance between the catalyst and the exhaust port is short, when fresh air is introduced, the mixture of exhaust gas and fresh air is insufficient, which delays oxidation and reduces the conversion efficiency of the catalyst. .

Exhaust gas flows only in the center of the catalytic converter and hardly flows around it, so the efficiency of catalyst utilization is extremely poor, resulting in localized deterioration of the catalyst and reduced oxidation conversion efficiency. It was hot. (Utility Model Application Publication No. 53-14017) In order to eliminate these conventional drawbacks, this invention creates a vortex in the exhaust gas flowing into the catalytic converter to effectively utilize the catalyst and increase the oxidation conversion efficiency. The present invention provides an exhaust gas purification device.

Embodiments of this invention will be described below based on the accompanying drawings.

In FIG. 1, reference numeral 1 indicates an exhaust manifold that discharges exhaust gas from each cylinder 2;
A dome-shaped swirl chamber 4 is formed, and a honeycomb-shaped catalytic converter 6 is mounted below the swirl chamber 4.

The manifold branches 3a and 3b are connected to the center 0 of the swirl chamber 4 in such a way that the exhaust gas flows in from the tangential direction so as not to face each other, and the exhaust gas flows into the swirl chamber 4 from the manifold branches 3a and 3b. A strong vortex is generated in the exhaust gas along the dome-shaped inner wall surface 4a of the vortex chamber 4.

Further, 7 is a secondary air introduction device that introduces secondary air into the exhaust gas using exhaust pulsation or by an air pump, and supplies secondary air to each exhaust port 5 via a secondary air introduction pipe 8. do. In this way, a strong vortex is generated in the exhaust gas flow discharged from the cylinder 2 in the vortex chamber 4 formed at the gathering part of the manifold branches 3a and 3b, and this exhaust gas is introduced into the catalytic converter 6. Because the exhaust gas is rotated, it comes into full contact with the catalyst and is oxidized. Therefore, all of the catalyst can be effectively utilized without local deterioration of the catalyst, and the oxidation conversion efficiency can be significantly increased compared to conventional devices.

Furthermore, even if the secondary air introduction device 7 is attached to the exhaust manifold 1 to introduce fresh air into the exhaust gas, the exhaust gas and fresh air are transformed into a strong vortex in the vortex chamber 4 as described above. Because of this mixing, sufficient oxidation can be carried out even if the distance to the catalyst is short, and the advantages of a manifold catalyst (oxidation reaction of high-temperature exhaust gas) can be promoted.

As described above, the present invention has a dome-shaped vortex chamber in which the branches of a plurality of manifolds communicate and merge in a tangential direction so as not to face each other, and the dome-shaped vortex chamber mixes and agitates the exhaust gas composition to make the exhaust gas composition uniform. A honeycomb-type catalyst through which the heated exhaust gas flows only in the axial direction is disposed downstream of the swirl chamber, so that the swirl chamber into which high-temperature exhaust gas from the exhaust manifold of each cylinder flows is formed in a dome shape, and the exhaust passage Since a honeycomb-type catalyst is installed in which the flow rate is limited in the axial direction, the cross-sectional area of the exhaust passage does not expand rapidly, so the flow velocity of the inflowing exhaust gas does not decrease, and the flow rate of the inflowing exhaust gas is prevented from decreasing. As a result, a strong vortex is generated in the dome-shaped vortex chamber, and the exhaust gas is uniformly mixed and stirred. Moreover, the ratio of the surface area of the dome-shaped vortex chamber to its volume is Since it is smaller than an annular swirl chamber, the drop in exhaust temperature is small, and as a result, the temperature distribution of the exhaust gas is uniform over the entire surface of the honeycomb catalyst, resulting in efficient catalytic reaction over the entire area. This has the effect of preventing damage and contamination of the catalyst due to localized high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a plan view of this invention, and FIG. 2 is a longitudinal sectional front view taken along the line - in FIG. 1. 6... Catalytic converter, 4... Vortex chamber, 1...
Exhaust manifold, 3a, 3b...manifold branch.

Claims (1)

[Scope of utility model registration request] It has a dome-shaped vortex chamber in which branches of a plurality of exhaust manifolds communicate and merge in a tangential direction so as not to face each other, and the exhaust gas is mixed and agitated in the dome-shaped vortex chamber to make the exhaust composition uniform only in the axial direction. An exhaust gas purification device characterized in that a flowing honeycomb catalyst is disposed downstream of the swirl chamber.