US Patent 7900609 Dual exhaust gas recirculation valve

An exhaust gas recirculation (EGR) system communicates hot exhaust gases from an exhaust manifold to an intake manifold through a first passage and a second passage parallel with the first passage. A first EGR valve assembly controls exhaust gas flow through the first passage and a second EGR valve assembly controls exhaust gas flow through the second passage. Exhaust gas is selectively flowed through one or both of the first and second passages to provide the desired temperature and flow through the intake manifold to the engine.