The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 29, 1984
Filed:
Aug. 24, 1982
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An exhaust gas cleaning system for an internal combustion engine having an exhaust system leading to an exhaust port of an engine body. The exhaust gas cleaning system comprises a TWC catalyst disposed in the exhaust system for simultaneously cleaning HC, CO and NO.sub.X in exhaust gas flowing through the exhaust system. A secondary-air supply passage is connected to the exhaust system on the upstream side of the TWC catalyst and coupled to the atmosphere. A check valve is disposed in the secondary-air supply passage, wherein the check valve is opened by the exhaust gas pulsation generated in the exhaust system and a secondary air control valve is positioned in the secondary-air supply passage on the upstream side of the check valve, wherein the secondary-air control valve increases the flow rate of the secondary air supplied to the exhaust system in the low-speed revolution range of the engine and decreases the flow rate of the secondary air supplied to the exhaust system in the accelerating and high-speed revolution ranges of the engine such that the atmosphere of the TWC catalyst becomes oxidative in the low-speed revolution range of the engine while the catalyst atmosphere becomes close to that of a stoichiometric ratio in the accelerating and high-speed revolution ranges.