| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylinder intake fresh air amount estimating device eliminating the necessity of retrieval of a table using a large number of parameters as an argument and capable of accurately and algebraically estimating intake fresh air amount in a cylinder. SOLUTION: This device is applied for an internal combustion engine in which an overlap period (VOL period) when both an intake valve and an exhaust valve are opened is set. On the assumption that gas pressure Pc in the cylinder is maintained at a certain level by exhaust gas pressure Pe during the VOL period, is decreased from the exhaust gas pressure Pe to intake gas pressure Pm in accordance with an adiabatic expansion process from the completion of the VOL period to the time when burned gas blown back to an intake passage begins to be sucked again to inside of the cylinder and then is maintained at a certain level by the intake gas pressure Pm from the time when the burned gas begins to be sucked again to the time when the intake valve is closed, this device algebraically calculates intake fresh air amount in the cylinder, in accordance with an algebraic expression obtained by time quadrature of an expression regarding gas in the cylinder on the basis of the energy conservation law. COPYRIGHT: (C)2006,JPO&NCIPI
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