Method for effectively diagnosing the operational state of a variable valve lift device

A system for diagnosing the operational state of a variable valve lift device in an engine, the system comprising:

• a crankshaft;
• a camshaft that is positioned relative to the crankshaft to form a first camshaft phase angle;
• a camshaft phaser for operably controlling the camshaft phase angle;
• a variable valve lift device having at least two modes of operation;
• and
• an engine control module in operable communication with the camshaft phaser, wherein the engine control module:
• receives a first signal indicative of an estimated position of the variable valve lift device, the first signal having a first signal-to-noise ratio;
• determines that the first signal represents one of a first condition indicating that the variable valve is operating in 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 failing to indicate that the first signal is in the first condition or the second condition;
• and
• instructs the camshaft phaser to adjust 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.

A computer-readable medium having computer-executable instructions for performing 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 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.

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 falls within one of a first range indicating that the variable valve is operating in at least one of the two modes of operation, a second range indicating that the variable valve is not operating in said at least one of the two modes of operation, and a third range where the first signal is in both in the first range and the second range;
• and
• adjusting the camshaft relative to the crankshaft to establish a camshaft phase angle when the first signal is in the third range 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 range and the second range.