Crankcase integrity breach detection
First Claim
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1. A method for an engine, comprising:
- measuring pressure in a crankcase vent tube with a pressure sensor arranged therein; and
with a controller, determining whether an intake air filter is degraded based on the measured crankcase vent tube pressure and setting a diagnostic code if the intake air filter is degraded.
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Abstract
Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits.
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Citations
19 Claims
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1. A method for an engine, comprising:
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measuring pressure in a crankcase vent tube with a pressure sensor arranged therein; and with a controller, determining whether an intake air filter is degraded based on the measured crankcase vent tube pressure and setting a diagnostic code if the intake air filter is degraded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for an engine, comprising:
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measuring pressure in a crankcase vent tube with a pressure sensor coupled therein; estimating barometric pressure; and with a controller, determining whether an intake air filter is plugged based on a difference between the measured crankcase vent tube pressure and the estimated barometric pressure during conditions when manifold airflow is higher than a threshold, and if so, setting a diagnostic code to indicate that the intake air filter is plugged. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An engine system, comprising:
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an engine including an intake passage and a crankcase; an air filter coupled in the intake passage upstream of a compressor; a crankcase vent tube mechanically connected to the intake passage downstream of the air filter, the crankcase vent tube also mechanically connected to the crankcase via an oil separator, the crankcase vent tube located external to the engine; a sensor coupled in the crankcase vent tube for estimating a vent tube air flow and/or pressure; and a control system with computer readable non-transitory instructions stored in memory, including, instructions stored in the memory for;
during engine cranking, while manifold air flow is lower than a threshold;learning an offset of the crankcase vent tube sensor based at least on a barometric pressure estimate; and instructions stored in the memory for;
during engine running, while manifold air flow is higher than the threshold;correcting an output of the crankcase vent tube sensor based on the learned offset; and setting a diagnostic code that indicates filter plugging based on a deviation of estimated crankcase vent tube pressure from the barometric pressure estimate. - View Dependent Claims (17, 18, 19)
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Specification