Integral Backpressure Transducer

This EGR valve combines inputs of exhaust backpressure and EGR port vacuum into one unit. Both inputs are required for the valve to operate. There are two types of exhaust backpressure valves, poppet and tapered pintle. The integral backpressure transducer valve combines an exhaust gas backpressure transducer within its diaphragm housing. The transducer controls EGR function by venting control vacuum in relation to exhaust backpressure. In order for this valve to operate, sufficient exhaust backpressure is required to close a bleed valve located inside the vacuum diaphragm housing. Until this bleed valve closes all vacuum routed to the valve has no effect. When the bleed valve closes vacuum is then applied to the diaphragm and the valve opens allowing exhaust gas to flow. Flow rate is dependent on source vacuum, exhaust pressure, control setting and orifice size.

Poppet type valves are rapid opening. Flow rate through this valve is limited by size of valve orifice or opening in carburetor spacer plate.

Internal tapered stem type valves use a pintle which moves the tapered portion of the valve up or down against its valve seat. Flow rate is determined by the amount of movement off the seat.