Control device for internal combustion engine and method for controlling internal combustion engine

摘要

Provided is a control device for an internal combustion engine, capable of controlling acceleration-response characteristics, performing an operation at an optimal fuel-efficiency point, and learning variation factors in an internal combustion engine provided with a supercharger including a wastegate valve. A target throttle-valve upstream pressure is calculated based on a target charging efficiency and a rotation speed. An exhaust-gas flow rate is calculated based on an air/fuel ratio and an intake-airflow rate. A target compressor driving force is calculated based on a target intake-airflow rate and a target throttle-valve upstream pressure. A wastegate-valve control value is calculated from the exhaust-gas flow rate and the target compressor driving force by using the relationship in which the relation expression expressing the characteristics of the exhaust-gas flow rate and the target compressor driving force depends only on the wastegate-valve control value.

主权项

1. A control device for an internal combustion engine including: a throttle valve provided in an intake path of the internal combustion engine; a supercharger including a turbine provided in an exhaust path and a compressor provided in the intake path on an upstream side of the throttle valve, for rotating integrally with the turbine; a wastegate valve provided in a bypass passage for bypassing the turbine; and a wastegate-valve driving section for driving the wastegate valve to change a flow-path sectional area of the bypass passage,
the control device comprising a wastegate-valve control part including: a target throttle-valve upstream pressure computing section for calculating a target throttle-valve upstream pressure corresponding to a target value of a pressure on the upstream side of the throttle valve based on a target value of a charging efficiency of the internal combustion engine and a rotation speed of the internal combustion engine; an exhaust-gas flow-rate computing section for calculating an exhaust-gas flow rate based on an air/fuel ratio of the internal combustion engine and an actual in-cylinder fresh-air amount; a target compressor driving-force computing section for calculating a target compressor driving force based on a target value of an intake airflow rate and the target throttle-valve upstream pressure; and a wastegate-valve opening-degree computing section for calculating a wastegate-valve control value based on the exhaust-gas flow rate and the target compressor driving force, wherein the wastegate-valve control part uses a relationship of characteristics of the exhaust-gas flow rate and the target compressor driving force to calculate the wastegate-valve control value so as to control the wastegate-valve driving section, wherein the relationship varies based only on the wastegate-valve control value.