Intake and exhaust system for preventing the generation of condensed water and operating methods thereof

An intake and exhaust system for preventing generation of condensed water, the intake and exhaust system comprising:

• an intake pipe supplying external air to an engine;
• an exhaust pipe for discharging combustion gas from the engine;
• an exhaust gas recirculation (EGR) system circulating some of combustion gas from the exhaust pipe to the intake pipe;
• an active purging system compressing and supplying evaporation gas generated from a fuel tank to the intake pipe;
• and
• a control unit configured to control the EGR system and the active purging system, wherein the control unit is configured to:
• calculate a first saturated water vapor pressure based on temperature at a position between the EGR system and the intake pipe,
• calculate a second saturated water vapor pressure based on temperature of the intake pipe,
• select a smallest value among the calculated first and second saturated water vapor pressures, and compare the selected saturated water vapor pressure with a water vapor pressure of intake air flowing through the intake pipe, and
• reduce an EGR rate of the EGR system or a purging rate of the active purging system when the water vapor pressure of the intake air is equal to or greater than the selected saturated water vapor pressure.