Patent ID: 7063057
Filing Date: 2006-06-20
Classification: F01L,F02D,Y02T

Abstract:
1. A method for diagnosing the operational state of a variable valve lift device in an engine, the engine including a camshaft and a crankshaft, the variable valve lift device having at least two modes of operation and being associated with the camshaft and the crankshaft, the method comprising: providing a first signal indicative of an estimated position of the variable valve lift device, the first signal having a first signal-to-noise ratio; determining that the first signal represents one of a first condition indicating that the variable valve is operating in said at least one of the two modes of operation, a second condition indicating that the variable valve is not operating in said at least one of the two modes of operation, and a third condition where the first signal is not in the first condition or the second condition; and adjusting the camshaft relative to the crankshaft to establish a camshaft phase angle when the first signal is in the third condition so that the first signal has a second signal-to-noise ratio, wherein the second signal-to-noise ratio is greater than the first signal-to-noise ratio, whereby the operational state of the variable valve lift device is then identified as one of the first condition and the second condition.