Systems and methods for crankcase system diagnostics

A method comprising:

• sealing a crankcase of an engine from a vent hose that is part of a positive crankcase ventilation system;
• initiating cranking of the engine and monitoring a series of pressure pulsations during a monitoring window duration via a pressure sensor positioned between a crankcase oil separator and the vent hose;
• and
• indicating a presence or an absence of degradation based on the series of pressure pulsations and the monitoring window duration, wherein the crankcase oil separator includes one or more sealing flaps that close responsive to a pressure differential between the crankcase and the vent hose being within a predetermined threshold of a zero pressure differential;
• and
• wherein sealing the crankcase of the engine from the vent hose comprises the one or more sealing flaps closing based on the pressure differential between the crankcase and the vent hose being within the predetermined threshold of the zero pressure differential.

A system for vehicle, comprising:

• a crankcase of an engine including oil;
• an oil separator with one or more sealing flaps that selectively fluidically couple the crankcase to an air intake system of the engine by way of a vent hose that is part of a positive crankcase ventilation system;
• a crankcase pressure sensor positioned between the vent hose and the oil separator;
• and
• a controller with computer readable instructions stored on non-transitory memory that, when executed under conditions where the one or more sealing flaps are fully closed thereby sealing the crankcase from the vent hose, cause the controller to:
• via the crankcase pressure sensor, monitor an air intake system pressure profile during a monitoring window;
• infer a presence of degradation associated with the vent hose based on a relationship between a magnitude of the air intake system pressure profile and a duration of the monitoring window;
• and
• command mitigating action responsive to the presence of degradation.

A method for determining a state of a crankcase vent hose, comprising:

• assessing a state of the crankcase vent hose in response to a flap of an oil separator being in a closed position;
• not assessing the state of the crankcase vent hose in response to the flap of the oil separator being in an open position;
• and
• providing an indication of degradation in response to the assessed state of the crankcase vent hose.