Title:
RECIPROCATING FOUR-STROKE SPARK IGNITION INTERNAL COMBUSTION ENGINE
Document Type and Number:
Japanese Patent JP2018141456
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To suppress the discharge of unpurified harmful substances in a cold state by achieving the high efficiency of a reduction catalyst, saving resources and reducing costs by preventing the flow-in of secondary air to the reduction catalyst, and by arranging an oxidation catalyst at an upstream side as much as possible, and accelerating the light-off of both the catalysts, in a spark ignition internal combustion engine in which the reduction catalyst is arranged at an upstream side, and the oxidation catalyst is arranged at a downstream side, and which has an exhaust emission control device for supplying the secondary air to both the catalysts.SOLUTION: A main cause that secondary air supplied to a downstream side of a reduction catalyst flows back toward an upstream side in an exhaust pipe, and flows into the reduction catalyst is due to transportation by a positive pressure wave which progresses toward the upstream side from an exhaust pipe end. The positive pressure wave is generated by a negative reflection wave which is generated by the reflection of the positive pressure wave progressing toward the downstream side by the injection of an exhaust gas at the pipe end being a free end, and progresses toward the upstream side. In this invention, a reflector for partially imparting a characteristic of a fixed end to the exhaust pipe end is arranged, the negative reflection wave is canceled by generating a positive reflection wave, and the generation of the positive pressure wave which progresses toward the upstream side is prevented.SELECTED DRAWING: Figure 3
Inventors:
EDA MASATO
Application Number:
JP2017049182A
Publication Date:
September 13, 2018
Filing Date:
February 27, 2017
Export Citation:
Assignee:
KAABYUTEKKU JAPAN KK
International Classes:
F01N3/24; F01N1/08; F01N3/22; F01N3/28; F01N13/08; F02D9/02; F02D41/04; F04B35/00