Stepped idle return for multiair equipped engines with high aeration

摘要

A method and system for controlling the engine during a return to idle maneuver when the engine's oil is highly aerated. The system and method will implement a stepped return to idle maneuver when the engine oil has a predetermined amount of aeration. The predetermined amount of aeration is an amount that could cause an engine to stall due to valve lift loss if the engine speed were reduced to the idle speed in the conventional manner.

主权项

1. A method of controlling an engine of a vehicle to set a speed of the engine to a predetermined idle speed, the method comprising:
determining, by a controller of the engine, an aeration of an oil utilized by a valve lift system configured to control valve lift of the engine; determining, by the controller, whether the oil aeration is greater than a predetermined aeration threshold indicative of a potential stall of the engine due to valve lift loss; when the oil aeration is greater than the predetermined aeration threshold, commanding, by the controller, the engine speed to an intermediate idle speed for a predetermined time period, the intermediate idle speed being greater than the predetermined idle speed; and in response to the predetermined time period expiring, commanding, by the controller, the engine speed to the predetermined idle speed.