Method and system for humidity sensor diagnostics
First Claim
Patent Images
1. A method of operating an engine including a humidity sensor, comprising,indicating humidity sensor degradation based on each of a change in an intake air relative humidity and temperature over a duration since an engine cold-start, the duration based on an exhaust catalyst temperature.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods and systems are provided for an engine including a humidity sensor. Degradation of the humidity sensor may be determined based on a change in intake air relative humidity as compared to a change in intake air temperature or pressure, under selected conditions. An amount of exhaust gas recirculated to an engine intake is adjusted differently based on whether the humidity sensor is degraded or functional.
20 Citations
19 Claims
-
1. A method of operating an engine including a humidity sensor, comprising,
indicating humidity sensor degradation based on each of a change in an intake air relative humidity and temperature over a duration since an engine cold-start, the duration based on an exhaust catalyst temperature.
-
9. A method of operating a turbocharged engine including a humidity sensor and a temperature sensor in an engine intake, comprising,
during an engine cold-start condition, estimating each of an intake air temperature and relative humidity over a duration since the cold-start; -
indicating humidity sensor degradation based on a change in the humidity relative to a change in the temperature over the duration; and adjusting an amount of exhaust gas recirculated from an engine exhaust to the engine intake based on the indication of humidity sensor degradation, the relative humidity indicative of likelihood of condensation at a turbocharger compressor, the adjusting including adjusting the amount to reduce condensation assuming a maximum relative humidity. - View Dependent Claims (10, 11, 12, 13, 14)
-
-
15. An engine system, comprising:
-
first and second parallel intake passages, each including a turbocharger compressor upstream of engine cylinders, the cylinders including a direct fuel injector; first and second parallel exhaust passages, each including a turbocharger turbine; a humidity sensor and a temperature sensor, each positioned only in the first passage; and a controller configured with instructions for indicating humidity sensor degradation responsive to a humidity change relative to a temperature change over a duration since an engine cold-start. - View Dependent Claims (16, 17, 18, 19)
-
Specification