NOX CONCENTRATION CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE, INTERNAL COMBUSTION ENGINE AND NOX CONCENTRATION CONTROL METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a NOx concentration control system for an internal combustion engine, the internal combustion engine and a NOx concentration control method for the internal combustion engine, which can calculate a NOx concentration while considering effects of humidity of the atmosphere, can improve calculation accuracy of the NOx concentration and thus can more appropriately control an operating state of the internal combustion engine by using a more accurate calculation value of the NOx concentration, so that the NOx concentration in exhaust gas of the internal combustion engine follows a target value.SOLUTION: Based on states of intake gas A+Ge and exhaust gas G relative to an engine 10, a calculation value Nc of a NOx concentration is calculated, and based on absolute humidity Ha of the atmosphere A sucked to an intake passage 12 of the engine 10, a humidity correction coefficient K is calculated. By using the calculated humidity correction coefficient K, control for correcting the calculated calculation value Nc of the NOx concentration is performed.SELECTED DRAWING: Figure 2