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Exhaust system of internal combustion engine

a technology of exhaust system and internal combustion engine, which is applied in the direction of exhaust treatment electric control, machines/engines, mechanical equipment, etc., can solve the problems of delay in heat-up of bypass catalyst converter, large catalyst time in bypass catalyst converter, and room for improvemen

Inactive Publication Date: 2009-05-21
CALSONIC KANSEI CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010]According to a first aspect of the present invention there is provided an exhaust system of an internal combustion engine including a main catalyst converter, a bypass catalyst converter, upstream-side main exhaust passages, a downstream-side main exhaust passage, bypass exhaust passages and a shift valve device. The main catalyst converter is used for purifying exhaust gas discharged from an internal combustion engine, while the bypass catalyst converter, also used for purifying the exhaust gas converter, has a volume smaller than a volume of the main catalyst converter. The bypass catalyst converter is arranged at a position closer to exhaust ports of the internal combustion engine relative to a position of the main catalyst converter. The upstream-side main exhaust passages include upstream-side portions and downstream-side portions having a collecting portion, and the downstream-side main exhaust passage has an upstream-side portion and a downstream-side portion, where the upstream portion thereof is connected with the collecting portion of the upstream-side main exhaust passages, and the

Problems solved by technology

The above known conventional exhaust system of the internal combustion engine, however, encounters a problem in that there is a room for improvement in the rise of heat in the bypass catalyst converter because of the following reason.
In the conventional exhaust system, junctions of the bypass exhaust passages are far away from the shift valves, so that considerable amount of the exhaust gas flows into portions of the upstream-side main exhaust passages between the junctions and the shift valves, consequently causing delay in heat-up of the bypass catalyst converter.
It takes much time for the catalyst in the bypass catalyst converter to reach catalyst activation temperature.

Method used

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  • Exhaust system of internal combustion engine
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  • Exhaust system of internal combustion engine

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Experimental program
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first embodiment

[0043]The operation of the exhaust system of the first embodiment will be described.

[0044]When the engine starts, its temperature does not reach normal running one and the exhaust system including the catalyst converters 5 and 9 are not warmed. In addition, the engine is normally driven not run at high engine speed. Consequently, the exhaust gas is discharged from the cylinders #1 to #4 to the inner space O of the shift valve units 6 through the exhaust port 1A to 1D and the mounting tubes 2a. At this time, the shift valve units 6 are shifted to the first shift position, where the rotatable arm 63 is placed at the position indicated by the alternate long and short dash line in FIG. 5 to block the upstream-side main exhaust passages from the inner space O while the upstream-side bypass exhaust passages 7a to 7d are communicated with the inner space O.

[0045]Therefore, the exhaust gas from the cylinders #1 to #4 is introduced into the bypass catalyst converter 9 through the passages 7a...

second embodiment

[0052]Next, an exhaust system of a second embodiment according to the present invention will be described.

[0053]The exhaust system of the second embodiment is constructed similarly to that shown in FIG. 1.

[0054]As shown in FIG. 6, in the exhaust system of the second embodiment, each shift valve unit 6 is integrally formed with a flange portion 6c having a plurality of through-holes at upstream side thereof. The shift valve unit 6 is fixed to a cylinder head of an engine through a head flange by a plurality of bolts 12 passing through the through-holes formed on the flange portion 6c.

[0055]The mounting tubes 2a of the first embodiment are removed in the second embodiment. The other portion and parts are constructed similarly to those of the first embodiment.

[0056]The exhaust system of the second embodiment has the following advantages in addition those of the first embodiment.

[0057]The shift valve units 6 can be fixed on the cylinder head 1 with high accuracy, which improves rotatio...

third embodiment

[0058]Next, an exhaust system of a third embodiment according to the present invention will be described.

[0059]The exhaust system of the third embodiment is constructed similarly to that shown in FIG. 1. A plurality of shift valve units 6 are shiftable between a first shift position and a second shift position. In the first shift position, upstream-side main exhaust passages 2 are closed and upstream-side bypass exhaust passages 7a to 7d are opened, so that exhaust ports 1A to 1D communicate with the upstream-side bypass exhaust passages 7a to 7d, respectively, being blocked off from the upstream-side main exhaust passages 2. In the second shift position, the upstream-side main exhaust passages 2 are opened and the upstream-side bypass exhaust passages 7a to 7d are closed, so that the exhaust ports 1A to 1D communicate with the upstream-side main exhaust passages 2, being blocked off from the upstream-side bypass exhaust passages 7a to 7d.

[0060]As shown in FIG. 7, a rotatable arm 6...

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PUM

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Abstract

An exhaust system of an internal combustion engine includes a main catalyst converter, a bypass catalyst converter, a bypass catalyst converter with a smaller volume and a shift valve device. Upstream-side main exhaust passages have a collecting portion connected with a downstream-side main exhaust passage connected with the main catalyst converter. Bypass exhaust passages have the bypass catalyst converter therein, being connected between the shift valve device and the downstream-side main exhaust passage. The shift valve device is disposed at a position from the upstream-side portions of the upstream-side main exhaust passages to a head flange fixable to a cylinder head of the engine to be shiftable between a first shift position where the upstream-side main exhaust passages are closed and the bypass exhaust passages are opened and a second shift position where the upstream-side main exhaust passages are opened.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an exhaust system of internal combustion engine which is provided with a main catalyst converter and a bypass catalyst converter in order to purify exhaust gas discharged from the engine.[0003]2. Description of the Related Art[0004]A conventional exhaust system of an internal combustion engine is disclosed in Japanese Patent Application Laying-Open publication No. 2007-46556. This conventional exhaust system includes upstream-side main exhaust passages, downstream-side main exhaust passages, bypass exhaust passages, a main catalyst converter, bypass catalyst converter, and two shift valves. The upstream-side main exhaust passages are attached to exhaust ports of an internal combustion engine, and their downstream-side portions are connected with upstream-side portions of the downstream-side main exhaust passages through the two shift valves. The main catalyst converter is connected with ...

Claims

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Application Information

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IPC IPC(8): F01N9/00
CPCF01N3/0814F01N13/009F01N3/2053F01N3/0835
Inventor SASAKI, NORIYOSHI
Owner CALSONIC KANSEI CORP