Patent ID: 9120366
Filing Date: 2015-09-01
Classification: B60H

Abstract:
1. A method of monitoring for a clogged or an unclogged state of an air filter in an automotive HVAC system, wherein the HVAC system includes a blower having a blower motor providing a driven airflow, a plurality of outlet registers controllable to provide a plurality of circulation modes, and an evaporator for selectably cooling the driven airflow, wherein the air filter passes the driven airflow, the method comprising the steps of: entering a baseline condition, wherein the baseline condition includes applying a moisture purge to the evaporator and selection of a predetermined circulation mode; controlling the blower motor to maintain a testing speed; quantifying an energization of the blower motor while maintaining the testing speed; comparing the energization to a base value derived according to the baseline condition with the air filter in an unclogged state; triggering a replacement action when the energization is greater than the base value; and wherein the method of monitoring of the air filter is performed in a plurality of baseline conditions each corresponding to a respective circulation mode, wherein a plurality of base values are stored according to respective baseline conditions, and wherein the method further comprises the step of selecting a base value for use in the comparing step according to the predetermined circulation mode present in the HVAC system.