Exhaust gas recirculation with condensation control

摘要

A system for providing exhaust gas recirculation in a multi-cylinder compression ignition internal combustion engine include an EGR valve in communication with an exhaust side of the engine to selectively divert a portion of the exhaust through an EGR circuit to an intake side of the engine and a two-pass, full flow EGR cooler disposed within the EGR circuit having a cross-sectional area sized to increase EGR flow rates and reduce fouling. In one embodiment, a bypass valve is positioned downstream of the EGR valve and upstream of the EGR cooler to selectively divert at least a portion of recirculated exhaust gas around the EGR cooler based on engine operating conditions to reduce or eliminate condensation of the recirculated exhaust gas. A condensation trap may be positioned downstream of the EGR cooler to collect any EGR condensate which is subsequently vaporized using an associated electric heater having appropriate piping to bypass the turbocharger and deliver the gaseous mixture to the tailpipe. The EGR cooler bypass may be used alone or in combination with the condensation trap depending upon the particular application. A charge air cooler bypass valve may also be provided alone or in combination with the EGR cooler bypass and/or condensation trap(s).