Technician A says that exhaust manifolds can be made from hard plastic or aluminum. Technician B says that many intake manifolds have an EGR valve that regulates the amount of recirculated exhaust that enters the engine in order to increase NO_xemissions. Who is right?

Question

Quizplus · Accepted Answer

Exhaust manifolds are typically made from materials that can withstand high temperatures, such as cast iron or stainless steel, not hard plastic or aluminum. While many intake manifolds may work in systems that have an EGR (Exhaust Gas Recirculation) valve, the EGR valve itself is not a component of the intake manifold but rather a separate component designed to recirculate exhaust gases back into the engine to reduce NOx emissions, not to increase them.

Technician a Says That Exhaust Manifolds Can Be Made from Hard