CPC F01N 11/00 (2013.01) [F01N 3/021 (2013.01); G01N 22/00 (2013.01); F01N 2550/04 (2013.01)] | 14 Claims |
1. An engine assembly for determining an estimate of soot load in a diesel particulate filter of the engine assembly, the engine assembly comprising an engine control module and a radio frequency soot sensor, the engine control module configured to:
receive a first mean attenuation value derived from attenuation values for each of a first plurality of radio frequencies within a first band of radio frequencies detected by the radio frequency sensor;
receive first standard deviation data for the mean attenuation value relating to the first plurality of radio frequencies within the first band of radio frequencies;
determine whether the first standard deviation data exceeds a standard deviation threshold;
(a) in the event that the first standard deviation data does not exceed the standard deviation threshold:
use the first mean attenuation value to infer a value for soot load in the diesel particulate filter;
(b) in the event that the first standard deviation data exceeds the standard deviation threshold:
receive a second mean attenuation value derived from attenuation values for each of a second plurality of radio frequencies within a second band of radio frequencies;
receive second standard deviation data relating to the mean attenuation value for a second plurality of radio frequencies within the second band of radio frequencies detected by the radio frequency sensor; and
in the event that the second standard deviation data does not exceed the standard deviation threshold:
use the second mean attenuation value to infer the value for soot load in the diesel particulate filter.
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