Abstract: An air metering valve or supplemental air valve connectable in the PCV system of an internal combustion engine having a shiftable valving member which regulates the quantity of supplemental air introduced into the PCV return. The valve spool is spring biased to the open position by a calibration spring. Pressure chambers are formed on opposite sides of the actuating pistona nd connectable to engine vacuum sources. As the degree of vacuum varies in the vacum sources, the valve spool shifts between an open and closed position. The valve may also be used to provide supplemental ambient combustion air under vacuum control independent of the PCV system. In another embodiment of the invention, the major valve components such as the valve body and shiftable valving member are fabricated from suitable plastic materials.

Abstract: An air metering valve or supplemental air valve connectable in the PCV system of an internal combustion engine having a shiftable valving member which regulates the quantity of supplemental air introduced into the PCV return. The valve spool is spring biased to the open position by a calibration spring. Pressure chambers are formed on opposite side of the actuating piston and connectable to engine vacuum sources. As the degree of vacuum varies in the vacuum sources, the valve spool shifts between an open and closed position. The valve may also be used to provide supplemental ambient combustion air under vacuum control independent of the PCV system.