Sutro LLP Cushman Darby & Cushman Intellectual Property Group of Pillsbury Madison &
Exhaust gas purification apparatus
 Two flow paths separated by a partition wall having a bore formed downstream of a catalyst unit provided in an exhaust pipe of an internal combustion engine. Adsorption means for adsorbing an HC component of an exhaust gas of the internal combustion engine is provided in one of the flow paths. When a temperature of the exhaust gas is above a predetermined level, the exhaust gas flows through the other flow path by means of a change-over valve. Because the bore is provided in the partition wall, the adsorption means is exposed to the exhaust gas and the HC component adsorbed by the adsorption means is easily desorbed because of the high temperature of the exhaust gas. A one-way valve which repeatedly performs an opening/closing operation due to pulsation of the exhaust gas, is provided between recirculation flow pipes. A position of the one-way valve between the recirculation flow pipes is determined so that a phase difference between the exhaust gas pulsation applied to the valve from the upstream side of the catalyst unit and the exhaust gas pulsation applied to the valve from the flow path of the adsorption means, inverts substantially by half-wavelength producing a large differential pressure applied to both the front and rear surfaces across the one-way valve, thereby rapidly recirculating the desorbed HC from the adsorption means to the catalyst unit. When the change-over valve is operated to a position shown by a dotted line to flow the exhaust gas through the adsorption means, the flow-in velocity of the exhaust gas flowing into the adsorption means is made uniform by the rectifying plate, thereby improving HC or the like adsorbing efficiency. When the change-over valve is turned to a position shown by a solid line for opening the exhaust gas flow path, so that the exhaust gas flows through the exhaust gas flow path, the rectifying plate prevents vortices from occurring on the upstream side of the adsorption means to thereby keep the once-adsorbed HC or the like from flowing out toward the exhaust gas pipe. 
Nippondenso Co., Ltd.
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Mamoru Makoto Hiroyuki Masakazu Hiroshi Takahiko
Mabuchi Saito Usami Tanaka Mori Yamamoto