Dual throttle for improved tip-out stability in boosted engine system

摘要

A method for providing intake air to an engine in a vehicle includes forming a mixture of fresh air and treated exhaust, and compressing the mixture upstream of a first throttle valve coupled to an intake manifold of the engine. The method further includes, during a higher engine-load condition, admitting the mixture to the intake manifold via the first throttle valve, and, during a lower engine-load condition, admitting fresh air to the intake manifold via a second throttle valve.