Method for preventing engine air flow calculation error and engine system thereof

An engine system including:

• a controller which is configured to classify an engine operation area of an engine into a sensor measurement deviation generation area, medium/high load areas, and a low load area, and is configured to classify, as an air flow calculation control applied to a cylinder charging amount of the engine, one of an air flow compensation control which applies a compensation measurement air flow to the sensor measurement deviation generation area, a manifold air pressure (MAP) air flow control which applies a measurement pressure to the medium/high load areas, and an HFM air flow control which applies a measurement air flow to the low load area;
• a hot-film air mass flow (HFM) sensor which detects an air flow applied to the compensation measurement air flow and the measurement air flow in an intake manifold of an intake system of the engine;
• a MAP sensor which detects an air pressure applied to the measurement pressure in the intake manifold of the intake system;
• an active purge system (AFS) which traps an evaporation gas of fuel, and sends the trapped evaporation gas to the intake system to purge the evaporation gas;
• and
• an exhaust gas recirculation (EGR) system which uses, as an exhaust gas recirculation (EGR) gas, and sends a predetermined amount of exhaust gases of the exhaust gases flowing through an exhaust system of the engine by the intake system.