Method and system for variable displacement engine diagnostics

Abstract

The present invention provides a method and a system for variable displacement engine diagnostics. The methods and systems are provided for diagnosing a cylinder valve deactivation mechanism in an engine system having cam-actuated valves. Movement of a latch pin of the deactivation mechanism is inferred from an induction current generated by a solenoid coupled to the latch pin, and the inferred movement is used to diagnose operation of cylinder valve deactivation mechanism. The inferred movement and a profile of the induction current is also used to estimate camshaft and crankshaft timing forimproved cylinder fuel delivery in the absence of a camshaft sensor.

Description

technical field [0001] The present application relates to a method and system for monitoring actuation of a cylinder valve deactivation mechanism in a variable displacement engine (VDE). Background technique [0002] The engine may include a cam-based system for controlling intake and exhaust valve timing. Wherein the cam is coupled to the camshaft. Because valves control the flow of air and fuel into engine cylinders for combustion, camshaft positions may be required so that accurate fueling and spark timing can be provided for reliable combustion and low emissions. For example, accurate and timely knowledge of camshaft position during engine starts may enable coordination of spark timing and fuel delivery in the engine and achieve more repeatable engine starts. [0003] Typically, an engine controller retrieves camshaft position information using a position sensor coupled to the camshaft. However, such sensors are expensive. Additionally, sensors may be prone to degrad...

AI Technical Summary

Problems solved by technology

In either case, fuel injection timing may not be set correctly without crankshaft information

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