Patent ID: 8286472
Filing Date: 2012-10-16
Classification: F01L,F01M,F02D,Y02T

Abstract:
1. A diagnostic system for a variable valve timing control system including a hydraulic variable valve timing controller adjusting a valve timing of an intake valve and/or an exhaust valve with a lubricant of an internal combustion engine and a diagnosis means for diagnosing the variable valve timing controllers, the diagnostic system comprising: an alcohol concentration determination means for detecting or estimating an alcohol concentration of a fuel supplied to the internal combustion engine; and a fuel diluting quantity estimation means for estimating a fuel diluting quantity based on the alcohol concentration, the fuel diluting quantity representing a fuel quantity mixed with the lubricant, wherein the diagnosis means includes a correcting means for correcting a determination condition based on the fuel diluting quantity, and the diagnosis means performs a diagnosis of the variable valve timing controller by means of said corrected determination condition.