CONTROL DEVICE AND CONTROL METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

Provided are a control device and a control method for an internal combustion engine, which enable a throttle-valve upstream pressure through simple calculation processing without being affected by a state of an opening degree of a wastegate valve (WGV). When a wastegate (WG) command value to a WGV driving section (212) for driving a WGV (33a) provided in a bypass passage (33) which bypasses a turbocharger (32) is to control supercharging to be weakened to the lowest level, the throttle-valve upstream pressure is estimated from an exhaust-gas amount. Otherwise, a value obtained by adding a preset value to an intake-manifold pressure is used as a throttle-valve upstream pressure estimate value. As a result, the throttle-valve upstream pressure is estimated with high accuracy by an inexpensive configuration without mounting a throttle-valve upstream pressure sensor, and then engine control is performed.

主权项

1. A control device for an internal combustion engine, comprising:
a throttle valve provided in an intake path of the internal combustion engine; a throttle-valve driving section for driving the throttle valve; a supercharger comprising a turbine provided in an exhaust path of the internal combustion engine and a compressor provided in the intake path so as to be located upstream of the throttle valve, the compressor rotating integrally with the turbine; a wastegate valve provided in a bypass passage which is provided to the exhaust path so as to bypass the turbine; a wastegate-valve driving section for driving the wastegate valve to change a sectional area of a flow path of the bypass passage; a wastegate command-value calculating section for calculating a control command value to the wastegate-valve driving section; an intake-manifold pressure detecting section for detecting a pressure value of an intake manifold provided in the intake path so as to be located downstream of the throttle valve; an intake-air amount detecting section for detecting an intake-air amount of the internal combustion engine; an air/fuel ratio detecting section for detecting an air/fuel ratio of an exhaust gas of the internal combustion engine; an exhaust-gas amount calculating section for calculating an exhaust-gas amount based on the intake-air amount detected by the intake-air amount detecting section and the air/fuel ratio detected by the air/fuel ratio detecting section; and a WG0P2 calculating section for calculating a WG0P2 estimate value which is an estimate value of a throttle-valve upstream pressure in the intake path at a position located downstream of the supercharger and upstream of the throttle valve based on the exhaust-gas amount when assuming that the control command value to the wastegate-valve driving section is 0%, wherein when the control command value to the wastegate-valve driving section is 0%, the WG0P2 estimate value calculated by the WG0P2 calculating section is set as a throttle-valve upstream pressure estimate value to calculate a target opening degree of the throttle valve based on the throttle-valve upstream pressure estimate value, the pressure value of the intake manifold, and a target air amount to drive the throttle valve based on the calculated target opening degree.