Exhaust device for internal combustion engine and control method for internal combustion engine

Abstract

An exhaust system for an internal combustion engine comprises an exhaust bypass (7) in parallel with an upstream portion of a main exhaust path (3) having a main catalytic converter (4) in a downstream portion thereof; an exhaust bypass catalytic converter (8) provided in the exhaust bypass (7); and a flow path switching valve (5) for blocking the main exhaust path (3) at the upstream portion thereof. The exhaust system includes an ignition timing adjustment mechanism for adjusting ignition timing to delay sparking when the flow path switching valve (5) is switched from the closed condition to the open condition thereof. A control method for the exhaust system is also disclosed.

Description

technical field [0001] The present invention relates to an exhaust device that uses a flow path switching valve to guide exhaust gas to a side of a bypass flow path provided with a catalytic converter upstream of the exhaust system after a cold start, and more particularly relates to correction when the flow path switching valve is switched. control. Background technique [0002] As is conventionally known, in a structure in which the main catalytic converter is arranged on the downstream side of the exhaust system such as under the floor of the vehicle, the catalytic converter cannot be activated after the cold start of the internal combustion engine until the temperature of the catalytic converter rises and is activated. A sufficient exhaust purification effect is expected. On the other hand, there is a problem that the closer the catalytic converter is to the upstream side of the exhaust system, that is, the internal combustion engine side, the more the catalyst deterio...

AI Technical Summary

Problems solved by technology

[0002] As is conventionally known, in a structure in which the main catalytic converter is disposed on the downstream side of the exhaust system such as under the floor of the vehicle, the cold start of the internal combustion engine During the period until the temperature of the catalytic converter is raised and activated, sufficient exhaust gas purification effect cannot be expected

On the other hand, there is a problem that the closer the catalytic converter is to the upstream side of the exhaust system, that is, the internal combustion engine side, the more the catalyst deteriorates due to heat, resulting in a decrease in durability.

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