| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of a conventional secondary air control system that acidic condensed water condensed on an inner surface of a valve housing or a surface of a valve element of a main valve made of an aluminum alloy, in which an exhaust gas component is dissolved, corrodes the valve housing of a solenoid valve and the valve element of the main valve, and deteriorates sealing performance of seal rubber of the main valve.SOLUTION: In a secondary air control system, a piping length of a connection piping 14 of a secondary air supply pipe 3 is set to be a length corresponding to a node (A) of exhaust pulsation, and thereby, exhaust pulsation generated in a secondary air control valve 1 and the secondary air supply piping 3 can be reduced when a solenoid valve is fully closed. Therefore, a reed valve 34 of a check valve is prevented from being opened in an engine speed in which the reed valve 34 resonates, and exhaust gas hardly flows into a first storage chamber 26 from a second storage chamber 37, and corrosion of a valve housing 22 of the solenoid valve or deterioration of sealing performance caused by acidic condensed water in which an exhaust gas component is dissolved can be prevented. |
