Engine variable oil pump diagnostic method
AssigneeFord Global Technologies, LLC
InventorAed M. Dudar
Life of this patent
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Abstract
Methods and systems are provided for diagnosing the functioning of a variable displacement oil pump. In one example, a method may include commanding a change in displacement of the variable displacement oil pump during a vehicle keyed-off condition and diagnosing a degradation of the oil pump based on a corresponding change in an estimated crankcase pressure.
Claims20
A method comprising:
- indicating degradation of a variable displacement oil pump (VDOP) based on a change in an estimated crankcase pressure, upon a commanded change in VDOP displacement.
The method of 5, wherein indicating degradation of the VDOP includes, estimating a second crankcase pressure during VDOP operation in the low displacement mode, and indicating that the VDOP is stuck in the high displacement mode responsive to the second crankcase pressure being lower than a second baseline pressure, the second baseline pressure lower than the first baseline pressure.
A method for an engine, comprising:
- during a key-off condition,
- estimating a first crankcase pressure while operating an oil pump in a high displacement mode;
- indicating that the oil pump is stuck in a low displacement mode based on the first crankcase pressure being lower than a first baseline pressure;
- and
- during a subsequent key-on condition, increasing an engine idle speed responsive to the indicating.
A hybrid vehicle system, comprising:
- an engine;
- an electric machine coupled to a battery capable of rotating the engine;
- a crankcase including a variable displacement oil pump mechanically coupled to an engine;
- a solenoid configured to adjust a displacement of the oil pump;
- a crankcase vent tube mechanically connected to an intake passage upstream of a compressor, the tube also mechanically connected to the crankcase;
- a crankcase pressure sensor coupled to the crankcase vent tube;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- during unfueled cranking of the engine via the electric machine,
- commanding a change in displacement of the variable displacement oil pump via the solenoid;
- sensing crankcase pressure via the crankcase pressure sensor before and after the commanded change in displacement;
- and
- indicating degradation of the oil pump based on the sensed crankcase pressure relative to a baseline pressure.
Dependencies are inferred from the claim text.