Patent ID: 8495909
Filing Date: 2013-07-30
Classification: F02B,F02D,Y02T

Abstract:
1. A cylinder pressure estimation device of an engine having a cylinder pressure sensor for detecting a pressure in a combustion chamber as a cylinder pressure, comprising: means for calculating as candidate values of an intake-valve-closing-time cylinder pressure, a plurality of candidate values of a possible pressure in said combustion chamber at an intake-valve-closing time which is a time when an intake valve closes; means for calculating as candidates of a cylinder pressure movement, a plurality of candidates of a possible movement of the pressure in said combustion chamber from said intake-valve-closing time to a post-intake-valve-closing time which is a time after said intake-valve-closing time by a predetermined time period on the basis of said candidate values of the intake-valve-closing-time cylinder pressure calculated by said intake-valve-closing-time cylinder pressure candidate value calculation means; means for calculating as a detected cylinder pressure movement, a movement of the cylinder pressure detected by said cylinder pressure sensor from said intake-valve-closing time to said post-intake-valve-closing time; and means for comparing said candidates of the cylinder pressure movement calculated by said cylinder pressure movement candidate calculation means with said detected cylinder pressure movement calculated by said detected cylinder pressure movement calculation means, determining the candidate of the cylinder pressure movement to be deemed to correspond to said detected cylinder pressure movement among said candidates of the cylinder pressure movement and determining as the pressure in said combustion chamber at said intake-valve-closing time, the candidate value of the intake-valve-closing-time cylinder pressure used for calculating said determined candidate of the cylinder pressure movement by said cylinder pressure movement candidate calculation means.