Crankcase integrity breach detection
First Claim
Patent Images
1. A method for an engine, comprising:
- boosting intake air with a compressor;
during engine cranking, while manifold airflow is lower than a threshold, increasing intake throttle opening of a throttle positioned downstream of the compressor; and
indicating crankcase ventilation system degradation based on a transient dip in crankcase vent tube pressure estimated by a sensor positioned within a crankcase vent tube following the intake throttle opening, the crankcase vent tube coupled upstream of the compressor.
1 Assignment
0 Petitions
Accused Products
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.
-
Citations
20 Claims
-
1. A method for an engine, comprising:
-
boosting intake air with a compressor; during engine cranking, while manifold airflow is lower than a threshold, increasing intake throttle opening of a throttle positioned downstream of the compressor; and indicating crankcase ventilation system degradation based on a transient dip in crankcase vent tube pressure estimated by a sensor positioned within a crankcase vent tube following the intake throttle opening, the crankcase vent tube coupled upstream of the compressor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method for an engine crankcase ventilation system, comprising:
-
flowing engine intake air through a turbocharger compressor; adjusting an actuator to raise an intake manifold vacuum to a threshold level; while holding the vacuum at the threshold level via the actuator, indicating crankcase ventilation system degradation based on a transient dip in a crankcase vent tube pressure estimated by a pressure sensor positioned in a crankcase vent tube coupled between an intake manifold and a crankcase, the vent tube coupled upstream of the compressor; and limiting boost based on the indication of crankcase ventilation system degradation. - View Dependent Claims (12, 13, 14, 15, 16)
-
-
17. An engine crankcase ventilation system, comprising:
-
an engine including an intake passage and a crankcase; a turbocharger with a compressor coupled in the intake passage; a crankcase vent tube mechanically connected to the intake passage upstream of the compressor, the tube also mechanically connected to the crankcase via an oil separator, the vent tube located external to the engine; an actuator coupled downstream of the compressor; a sensor coupled in the crankcase vent tube for estimating a vent tube air flow; and a control system with computer readable instructions for, during engine cranking, when manifold airflow is lower than a threshold flow, adjusting the actuator to raise an intake manifold vacuum to a threshold level; and while holding the vacuum at the threshold level, indicating crankcase ventilation system degradation based on differences between an estimated flow rate and an expected flow rate through the crankcase vent tube. - View Dependent Claims (18, 19, 20)
-
Specification