| 摘要 |
PURPOSE:To improve performance of purifying exhaust gas by changing secondary air supply for upstream an exhaust manifold or a catalytic onverter of an exhaust pipe according to the state of an engine. CONSTITUTION:A secondary air change-over valve 20 consists of a diaphragm chamber 22, a spring 23, and a valve element 24 and changes secondary air flow from an inlet port 21 to eigher outlet port 25 or 26 by negative pressure sent into the diaphragm chamber 22 to move the valve element 24. A primary negative pressure course 32 inciuding a pressure delay valve 30 and an engine cooling water sensing negative pressure change-over switch 40 and a secondary negative pressure course 34 including a negative pressure inlet valve 50 and an electromagnetic valve 16, parallely piped, connect the diaphragm chamber 22 of the secondary air change-over valve 20 with a suction manifold 4. |
