| 摘要 |
Various embodiments of air control valves are disclosed. Each has a mechanism, controlled by a solenoid and by the difference between fluid pressure at its inlet and fluid pressure at its outlet, for allowing communication between an air pump and an exhaust gas treatment system as long as fluid pressure at the outlet does not exceed fluid pressure at the inlet by more than a predetermined difference during absence of a predetermined electric energization of the solenoid, for disallowing communication between the air pump and the gas treatment system during presence of the predetermined electric energization of the solenoid, and for disallowing communication between the air pump and the gas treatment system whenever fluid pressure at the outlet exceeds fluid pressure at the inlet by more than the predetermined difference.
|
