The lean marginal control manner null due to

摘要

PURPOSE: To continue operation in an air-fuel ratio right before a torque fluctuation is produced by measuring the characteristics of an ion current flowing to a cylinder right after ignition, detecting a lean limit based on the characteristics, and increasing a fuel injection amount during detection of the lean limit. ;CONSTITUTION: Various detected signals from various sensors 13 17 and 21 to detect the running state of an engine 100 are inputted to an input interface 9 by means of an electronic control device. Meanwhile, various control signals are outputted from an output interface 11 to a fuel injection valve 5 and a spark plug 18. In this case, a power source 24 for a bias to measure an ion current is connected to a spark plug 18 through a high pressure diode 23. In which case, the characteristics of an ion current flowing to a cylinder 10 right after ignition are measured by an electronic control device 6. A lean limit is detected based on the characteristics of the measured ion current, and a fuel injection amount is increased when the lean limit is detected.;COPYRIGHT: (C)1994,JPO&Japio