| 摘要 |
A method for estimating the oxygen concentration in an internal combustion engine comprising an intake manifold, an exhaust manifold, an EGR system, a throttle valve, an air mass sensor for measuring a fresh air flow ( m thr ) entering the intake manifold through the throttle valve, a plurality of cylinders. According to the invention the method comprises the steps of estimating the total gas flow ( m o ) entering the cylinders, calculating the EGR gas flow ( m egr ), calculating the air fraction (f _air_em ) of the gas flowing in the exhaust manifold, calculating the air mass (m im_air ) entering the cylinders based on the air fraction (f _air_em ) in the exhaust manifold, on the total gas flow ( m o ) entering the cylinders, on the EGR gas flow ( m egr ) and on the fresh air flow ( m thr ), calculating the total mass (m im ) in the intake manifold based on the fresh air flow ( m thr ), on the EGR gas flow ( m egr ) and on the total gas flow ( m o ) entering the cylinders, calculating the air fraction (f air_im ) in the intake manifold based on the air mass (m im_air ) entering the cylinders and the total mass (m im ) in the intake manifold, and calculating the oxygen mass concentration ([O 2 ] m _ im ) in the intake manifold based on the air fraction (f air_im ) in the intake manifold. |
