Patent ID: 7055375
Filing Date: 2006-06-06
Classification: F02D,F02M,G01M,Y02T

Abstract:
1. A leakage detecting apparatus for an internal-combustion engine having a re-circulating passage for re-circulating an exhaust gas from an exhaust system to an air intake system in the engine, a re-circulating valve that is disposed in the re-circulating passage to control a flow rate of the re-circulating exhaust gas, and an A/F ratio sensor for detecting an A/F ratio of the exhaust system, said apparatus comprising: a first means for detecting an operation amount of the re-circulating valve; and a second means for calculating correlation between output of the operation amount detecting means and output of the A/F ratio sensor to determine leakage in the re-circulating passage, wherein the correlation is obtained by an inner product calculation of deviations of time-sequence vector of the output of said first means relative to an average value and deviations of a time-sequence vector of the output of the A/F ratio sensor relative to an average value, and wherein leakage in the re-circulating passage is detected when an accumulated value of the inner product over a predetermined period exceeds a threshold value.