Internal combustion engine with exhaust gas recirculation system

Claim 1

An internal combustion engine system having an engine proper and an intake manifold fluidly connected to said engine proper to convey an air-fuel mixture fed into the same, said engine system comprising: a first exhaust conduit section including a first inner shell member defining therein a first exhaust gas passage through which the exhaust gases from the engine proper are passed, and a first outer shell member substantially covering said first inner shell member to define between said first inner and outer shell members a first insulating space, said first inner shell member being formed with at least one opening to provide a fluid communication between said first exhaust gas passage and said first insulating space; a second exhaust conduit section including a second inner shell member defining therein a second exhaust gas passage through which the exhaust gases from said first exhaust gas passage of said first exhaust conduit section are passed before discharged into the open air, and a second outer shell member substantially covering said second inner shell member to define between said second inner and outer shell members a second insulating space, said second inner shell member being formed with at least one opening to provide a fluid communication between said second exhaust gas passage and said second insulating space; first conduit means for providing a fluid communication between said first insulating space and the interior of said intake manifold; and second conduit means for providing a fluid communication between said first and second insulating spaces.