Constant pressure relief valve for an air control valve.

摘要

A constant pressure relief valve (10) for an air control valve maintains the pressure in a secondary air system below a predetermined value. A diaphragm (18) divides the valve housing (12) into two chambers (24 and 28) wherein the first chamber (24) contains the inlet orifice (22) controlled by a valve member (20) and an exhaust orifice (16). The second chamber (28) contains a reference pressure and a valve bias spring (32) cooperating together to provide the constant pressure. Due to back pressures at the exhaust orifice (16), the lift of valve member (20) is increased to increase flow through the relief valve (10) maintaining the constant relief pressure.