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US 10,794,244 B2Granted
Method and system for crankcase ventilation monitor
AssigneeFord Global Technologies, LLC
InventorsIn Kwang Yoo, Michiel J. Van Nieuwstadt, Rui Chen
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for indicating crankcase breach due to disconnection of a crankcase vent tube from an engine on a clean air side or broken crankcase vent tube. In one example, a maximum possible change in crankcase vent tube pressure is estimated for each pedal transient of a drive cycle. The change for a plurality of transients in averaged and compared to a threshold to identify vent tube disconnection.
Claims20
An engine method, comprising:
- following each of a first set of qualifying pedal transients of a drive cycle, updating a minimum and maximum value of crankcase pressure;
- following each of a second set of qualifying pedal transients of the drive cycle, learning a pressure difference between a last updated minimum and maximum value of crankcase pressure;
- and
- indicating degradation in crankcase ventilation based on an average pressure difference over the second set.
1 more element
A method, comprising:
- during a first number of pedal transients where manifold air flow is within a range, updating maximum and minimum values of crankcase pressure based on crankcase pressure sensor output;
- during a second number of pedal transients where manifold air flow is outside the range, estimating a delta pressure based on last updated maximum and minimum values of crankcase pressure;
- and
- indicating crankcase breach responsive to the delta pressure, averaged over the second number, being lower than a threshold value.
1 more element
An engine system, comprising:
- a pedal for receiving an operator torque demand;
- an engine including an intake manifold and a crankcase;
- a crankcase vent tube mechanically connected to the intake manifold upstream of a compressor, the tube also mechanically connected to the crankcase via an oil separator, the vent tube located external to the engine;
- a pressure sensor coupled in the crankcase vent tube for sensing crankcase pressure;
- an air flow sensor coupled to the intake manifold;
- and
- a controller with computer readable instructions stored on non-transitory memory that when executed cause the controller to:
- indicate vent tube breach responsive to a mean crankcase pressure being lower than a threshold value, the mean crankcase pressure estimated over an integrated duration while manifold air flow exceeds an upper threshold;
- and
- indicate vent tube breach responsive to an average crankcase pressure range being lower than another threshold value, the average crankcase pressure range estimated over a number of pedal transients where manifold air flow exceeds the upper threshold and falls below a lower threshold.
7 more elements
Dependencies are inferred from the claim text.