| 摘要 |
PROBLEM TO BE SOLVED: To enable the reliable failure diagnosis of a cylinder internal pressure sensor degraded by various factors.SOLUTION: A cylinder internal pressure sensor diagnosis method comprises: calculating a calculation value of a cylinder internal pressure using a cylinder internal pressure calculation expression based on thermodynamics (S106); calculating a pressure difference between the calculated calculation value and a cylinder internal pressure detected by a cylinder internal pressure sensor a predetermined number of times in one cylinder cycle (S108, S110); calculating a standard deviation of the pressure differences obtained in one cylinder cycle in a predetermined number of cylinder cycles (S112 to S116); calculating an average value of the standard deviations obtained by executing the calculation in the predetermined number of cylinder cycles (S118); repeatedly executing counting by a counter if the average value deviates from a predetermined pressure difference range (S122, S128); and determining that a failure occurs to the cylinder internal pressure sensor if the count value of the counter exceeds a predetermined alarm reference value (S124, S126). |
