Methods and systems are provided for a particulate matter sensor positioned downstream of a diesel particulate filter in an exhaust system. In one example, a particulate matter sensor assembly may include an outer stepped tube, an inner stepped tube positioned within the outer tube, and a plate having sensor element positioned inside the inner tube, the inner and the outer tube generating a step in the assembly. The step may block larger contaminants and water droplets, and thereby stopping them from impinging on the sensor element positioned within the assembly.

A particulate filter having a porous ceramic honeycomb structure with a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of inner channels. Filtration material deposits are disposed on one or more of the wall surfaces of the honeycomb body. The highly porous deposits provide durable high clean filtration efficiency with small impact on pressure drop through the filter.

A system and method for purifying engine exhaust by using ozone; the system for purifying engine exhaust by using ozone comprises a reaction field (202), which is used to mix an ozone stream and an exhaust stream for reaction; the system has an excellent purification effect without needing to add a large amount of urea.

A vehicle particulate matter contamination recovery system includes a particulate matter filter receiving exhaust gas from an engine. A particulate matter sensor is positioned downstream of the particulate matter filter, the particulate matter sensor collecting a non-combustible contaminant on a circuit of the particulate matter sensor and generating a current indicating presence of the non-combustible contaminant. A total volume of water collected during multiple cold start operations of the engine is passed onto the sensor acting to at least partially dissolve the non-combustible contaminant. The particulate matter sensor is operated in a remedial action mode of operation having no voltage applied to the circuit of the particulate matter sensor until a quantity of the cold start operations corresponding to the total volume of water is reached.

In a control device for a particulate matter detection sensor, a voltage value acquiring unit acquires a sensor voltage value which is a value of a voltage being applied across a pair of electrodes in the particulate matter detection sensor. A current value acquiring unit acquires a sensor current value which is a value of a current flowing between the electrodes. An output unit outputs a PM current value corresponding to the amount of deposit of particulate matter on an element part of the particulate matter detection sensor. States which the particulate matter detection sensor is determined to be in by a state determining unit include a sensor failure state and a PM-deposited state. The state determining unit determines whether the particulate matter detection sensor is in the sensor failure state or the PM-deposited state based on the sensor voltage value and the sensor current value.

A method of using a radio frequency sensor for determining an estimate of soot load in a diesel particulate filter is disclosed, The method comprises: receiving 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; and receiving first standard deviation data for the mean attenuation value relating to the first plurality of radio frequencies within the first band of radio frequencies. The method further comprises: determining whether the standard deviation data exceeds a standard deviation threshold, In the event that the standard deviation data does not exceed a standard deviation threshold, the method uses the first mean attenuation value to infer a value for soot load in the diesel particulate filter, in the event that the standard deviation data exceeds a standard deviation threshold, the method comprises: receiving 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; and receiving 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, In the event that the second standard deviation data does not exceed the standard deviation threshold, the method uses the second mean attenuation value to infer the value for soot load in the diesel particulate filter.

Disclosed is a method for control of an activation of a fluid sensitive sensor of an exhaust treatment system arranged for treating an exhaust stream, which includes: determining an exhaust temperature and an exhaust mass flow for the exhaust stream; determining if there is liquid fluid present in the exhaust stream at the fluid sensitive sensor, respectively, based on: 1) an elimination time function, wherein the elimination time function is based on the determined exhaust temperature and the determined exhaust mass flow; and 2) a corresponding lengths of a time period needed to eliminate a predetermined amount of liquid fluid from the exhaust stream; and controlling an activation of said fluid sensitive sensor based on the determination of if there is liquid fluid present in the exhaust treatment system at the fluid sensitive sensor.

A device that includes a conduit, a first window, a second window, a first catalyzed layer, a second catalyzed layer, an optical source, and an optical detector is disclosed. The conduit may be configured to receive an exhaust gas. The first catalyzed layer may be disposed on the first window and the second catalyzed layer may be disposed on the second window. The first catalyzed layer and the second catalyzed layer may be configured to cause a reaction with soot in the exhaust gas at an activation temperature to reduce accumulation of the soot on the first window and the second window. The optical source may be configured to emit a beam of light into the conduit through the first window. The optical detector may be configured to receive at least a portion of the beam of light through the second window.

An exhaust gas aftertreatment system includes a first sensor configured to measure a parameter and a second sensor disposed proximate the first sensor and configured to measure the parameter. The system includes a controller configured to initially utilize the first sensor as a primary sensor. At target intervals, the controller is configured to receive a first sensor value from the first sensor and receive a second sensor value from the second sensor. The controller is configured to calculate a difference between the first sensor value and the second sensor value and determine if the difference between the first sensor value and the second sensor value is greater than a threshold value. If the difference between the first and second sensor values is greater than the threshold value, the controller is configured to stop utilizing the first sensor as the primary sensor and utilize the second sensor as the primary sensor.

A particulate matter sensor includes a sensing element with a first electrode and a second electrode, an inner shield with the sensing element disposed therein, and an outer shield with the inner shield disposed therein. The inner shield includes a first portion with an inner shield inlet and a second portion which is smaller in diameter that the first portion such that the first and second electrodes are within the second portion. The outer shield includes an outer shield inlet which communicates exhaust gases to the inner shield inlet.