Automatic initiation system for regenerating a particulate filter trap

Abstract

A method and apparatus is disclosed for initiating the energization of a regenerative apparatus used with a particulate filter trap having a porosity effective to extract particulates from the exhaust gas flow of an internal combustion engine. The method comprises: (1) sensing the actual pressure drop across the filter trap and sensing the pressure drop across an open channel simulative filter structure; (2) converting the pressure drops to proportional voltages and ratioing the voltage of the filter trap pressure drop to the product of a constant and the voltage of the simulative filter structure pressure drop; and (3) using the resultant voltage ratio to control the energization of the regeneration apparatus when the output exceeds a predetermined allowable limit, e.g., 2-8 volts. The apparatus employs a simulative filter structure fabricated of the same monolithic honeycomb celled ceramic as is the filter trap, except that the structure has a controlled porosity effective to permit the passage of substantially all particulates in the gas flow therethrough.

Dependencies are inferred from the claim text.