An intake-air control of SI engine using Smith method

Abstract

An electronic control throttle is equipped in gasoline spark-ignition engines to improve the response of intake-air control system. However, because there is a dead time in discrete combustion process with 4-stroke engine, it's difficult to make dynamic control, when lean/rich air fuel ratio transitions and engine torque fluctuate significantly, intake-air control delay becomes a hard problem. In this paper, for intake-air control to improve response of intake-air control, the Smith compensation and various kind of linear dynamic delay compensation are investigated. It is confirmed that control is efficient by simulation of idle speed control with modified air intake control.