Patent ID: 7073484
Filing Date: 2006-07-11
Classification: F02D

Abstract:
1. An internal combustion engine control apparatus that performs open/close control of an ISC valve provided in a bypass pipe to adjust a quantity of air passing through the bypass pipe, the bypass pipe being provided secondarily to an air intake pipe for supplying air to an engine so as to connect portions before and behind a throttle valve, the apparatus comprising: an operation state determining section for determining whether the engine is in a running state or an idle state according to a signal from an external sensor; an engine revolution speed detecting section for detecting revolution speed of the engine according to a signal from another external sensor; a running time control value setting unit which sets an open/close control value for the ISC valve such that the control value increases and the valve opens as the revolution speed of the engine increases, while the engine is in the running state; and an idle time control value setting unit which sets the open/close control value for the ISC valve such that the engine reaches a preset target revolution speed while the engine is in the idle state, and provides a lower limit value to the open/close control value during a predetermined period of time after the engine is switched from the running state to the idle state and sets the control value not to be smaller than the lower limit value, wherein said idle time control value setting unit comprises: an engine revolution speed deviation detecting section for obtaining a deviation between a current engine revolution speed from said engine revolution speed detecting section and the target revolution speed; a correction amount setting section for setting a correction amount of the open/close control value for the ISC valve based on a correction amount map preset from the deviation; a correction amount adding/subtracting section for adding/subtracting the correction amount to/from a current control value; a timer section for generating a timer signal indicating a predetermined period of time after the engine is switched from the running state to the idle state according to a determination of said operation state determining section; and an idle time control value setting section for setting the control value for the ISC valve according to a control value from said correction amount adding/subtracting section, and limiting and setting a lower limit of the control value from said correction amount adding/subtracting section to a preset lower limit limiting value during a period of time while the timer signal is present.