SYSTEMS AND METHODS FOR ON-BOARD CYLINDER LEAKDOWN TESTING

摘要

Methods and systems are provided for performing an onboard cylinder leakdown test in response to an indication of cylinder misfire. In one example, following an engine-off event and an engine temperature above a threshold, fuel is injected into the indicated cylinder under conditions wherein the cylinder is expected to be sealed, and the detection of hydrocarbon migration out of the cylinder indicates cylinder degradation. In this way, cylinder degradation may be accurately diagnosed without intrusive, time consuming, and difficult off-board cylinder leakdown tests.

主权项

1. A method for an engine, comprising:
during a first condition, including an engine-off condition, injecting a quantity of fuel into a first cylinder of the engine while maintaining an intake valve and an exhaust valve of the first cylinder closed; and indicating degradation of the first cylinder responsive to hydrocarbon migration out of the cylinder.