Patent ID: 7909018
Filing Date: 2011-03-22
Classification: F02D,F02P

Abstract:
1. A control apparatus for determining a firing timing of an internal-combustion engine, comprising: in-cylinder pressure detecting means for detecting an in-cylinder pressure at a predetermined time interval; in-cylinder pressure calculating means for calculating an in-cylinder pressure for every predetermined crank angle based on the in-cylinder pressure detected at the predetermined time interval; means for estimating a motoring pressure in a case where combustion is not performed in the engine; detecting means for detecting that a pressure difference between the calculated in-cylinder pressure and the motoring pressure has exceeded a determination value; and firing timing identifying means for identifying, as a firing timing, a time point at which the pressure difference has exceeded the determination value with a finer resolution than the resolution of the predetermined crank angle by an interpolation calculation, the interpolation calculation using a first crank angle at which it is detected that the pressure difference has exceeded the determination value, the pressure difference corresponding to the first crank angle, a second crank angle previous to the first crank angle by the predetermined crank angle, and a pressure difference corresponding to the second crank angle, wherein a value equivalent to a predetermined ratio of the motoring pressure at a compression top dead center is used as the determination value.