| 摘要 |
<p>An air control valve for a vehicle emissions control system has an inlet connected to the output of the vehicle air pump, a first outlet connected to exhaust injection passages in cylinder head, and a second outlet connected downstream into the exhaust manifold. A vacuum actuated valve element is responsive to engine manifold vacuum to divert the output of the air pump from the downstream injection point to the upstream injection point during cold engine operation. However, the air supply from the air pump is diverted from the upstream injection point to the downstream injection point for a few seconds when a sudden increase in manifold vacuum occurs, such as during engine deceleration when the engine is cold. After the engine warms up, the air supply from the air pump is continuously communicated to the downstream injection point.</p> |
