Patent ID: 9228519
Filing Date: 2016-01-05
CPC Classification: F02D

Claim Text:
1. An estimation device for a cylinder intake air amount in an internal combustion engine, which serves for estimating a cylinder intake air amount sucked into a cylinder in the internal combustion engine which is connected to an intake pipe at a location downstream of a throttle valve, said estimation device comprising: a variety of kinds of sensors that detect operating states of said internal combustion engine related to a variety of kinds of actuators; and a physical model that models a response delay of an intake system until the air having passed through said throttle valve comes into said cylinder, by using detected values of said variety of kinds of sensors as input information; wherein said variety of kinds of actuators include a throttle opening degree control unit that regulates an amount of air passing through said throttle valve by controlling a throttle opening degree of said throttle valve thereby to change an effective opening area thereof; wherein said variety of kinds of sensors include: an atmospheric air temperature sensor that detects an atmospheric air temperature at an atmospheric air side of said throttle valve; an atmospheric air pressure sensor that detects an atmospheric air pressure at the atmospheric air side of said throttle valve; and an intake manifold pressure sensor which detects a pressure in the intake pipe at a downstream side of said throttle valve as an intake manifold pressure; wherein said physical model includes: a volumetric efficiency corresponding value calculation unit that calculates a volumetric efficiency corresponding value which is an index indicating said cylinder intake air amount; a throttle opening degree learning unit that calculates a learning corrected target throttle opening degree for achieving a target amount of intake air by learning a relation between said throttle opening degree and said effective opening area; and a cylinder intake air amount calculation unit that calculates said actual cylinder intake air amount; wherein at the time of steady state operation, the estimation of said actual cylinder intake air amount by said cylinder intake air amount calculation unit is carried out by using said intake manifold pressure and said volumetric efficiency corresponding value, and at the same time, opening degree learning by said throttle opening degree learning unit is carried out based on said actual cylinder intake air amount, whereas at the time of steady state operation, after the opening degree learning by said throttle opening degree learning unit is stopped, an amount of intake air having passed through the throttle valve is estimated by applying the actual effective opening area calculated from said throttle opening degree and a result of said opening degree learning, said intake manifold pressure, said atmospheric air pressure and said atmospheric air temperature to a flow rate calculation expression of a throttle type flow meter, and at the same time, the calculation of said actual cylinder intake air amount by said cylinder intake air amount calculation unit is carried out based on said amount of intake air.