A particulate sensor can reduce the amount of floating ions discharged from the interior of a gas introduction pipe to the outside through a gas discharge opening, without providing an auxiliary electrode member which applies to the floating ions a repulsive force toward the gas introduction pipe to thereby assist the collection of the floating ions by the gas introduction pipe. The particulate sensor has an collection member which is connected to a gas introduction pipe to thereby be maintained at a collection potential and is disposed in the interior of the gas introduction pipe to be located between a forward end of the discharge electrode member and a gas discharge opening such that the forward end of the discharge electrode member cannot be visually recognized from the outside of the gas introduction pipe through the gas discharge opening.

Methods and systems are provided for a particulate matter sensor. In one example, the sensor may include a concave inlet for admitting exhaust gas from an exhaust passage downstream of a particulate filter into the sensor.

A honeycomb body 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. A highly porous layer is disposed on one or more of the wall surfaces of the honeycomb body. The highly porous layer has a porosity greater than 90%, and has an average thickness of greater than or equal to 0.5 μm and less than or equal to 10 μm. A method of making a honeycomb body includes depositing a layer precursor on a ceramic honeycomb body and binding the layer precursor to the ceramic honeycomb body to form the highly porous layer.

There is provided the diagnostic device for a sensor which is arranged in an exhaust passage of an internal combustion engine and detects a particulate matter amount in exhaust, the diagnostic device including a time-rate-of-change calculation unit which calculates a time rate of change of the particulate matter amount detected by the sensor during a period in which a fuel injection amount of the internal combustion engine is equal to or less than a predetermined injection amount threshold, and an abnormality determination unit which determines an abnormality of the sensor based on the time rate of change of the particulate matter amount calculated by the time-rate-of-change calculation unit.

The present disclosure relates to exhaust gas emissions in motor vehicles. The teachings thereof may be embodied in soot sensors. For example, a soot sensor may include: a first electrode; a second electrode; an insulation body between the first electrode and the second electrode configured to allow soot particles to pass with a gas flow into a space defined between the first electrode and the second electrode; a meter evaluating a current between the first electrode and the second electrode resulting from an electrical voltage applied between the first electrode and the second electrode; and elements concentrating the electric field strength formed on at least one of a surface of the first electrode or a surface of the second electrode.

A particulate matter detection sensor has an accumulation section for accumulating a part of particulate matter particles contained in exhaust gas emitted from an internal combustion engine, and a pair of a first detection electrode and a second detection electrode formed on the accumulation section. The second detection electrode is formed separated from the first detection electrode. The first detection electrode has projecting parts which project toward the second detection electrode. Because a separation between the first and second detection electrodes is locally reduced at the projecting parts, the projecting parts attract and accumulate more particulate matter, and this structure makes it possible to allow the particulate matter detection sensor to have improved detection sensitivity.

Methods and systems are provided for a soot sensor. In one example, a method diverting exhaust gas from a main exhaust passage to a second exhaust passage comprising a soot sensor with a rotatable component configurable to capture soot.

Methods and systems are provided for reducing soot sensor electrode degradation in harsh chemical environment introduced as a result of desulfation of a lean NOx trap positioned upstream of the soot sensor. In one example, a method may include in response to the SOx load being higher than the threshold, prior to initiating desulfation of LNT, operating the soot sensor in a pre-desulfation mode where the negative electrode is connected to the positive electrode for a brief duration, while the positive electrode is disconnected from the positive electrode. However during desulfation, when H.sub.2S is released as a by-product, both the electrodes may be open, i.e. not connected to the positive electrode or ground, thereby reducing the possibility of sensor degradation.

A particle detection system (1) includes a particle sensor (10) having a detection section (11) exposed to a gas under measurement EG. The particle sensor (10) includes an insulating member (121, 100), and a heater section (150, 105) for heating at least a portion of the gas contact surface (121s, 101s) of the insulating member (121, 100). The particle detection system (1) includes adhesive restraining energization means (225, 223, S4, S10) for heating the gas contact surface (121s, 101s) to an adhesion restraining temperature Td at which adhesion of the particles S to the gas contact surface (121s, 101s) is restrained as compared with the case where the heater section is not energized, wherein adhering particles SA which are particles adhering to the gas contact surface (121s, 101s) burn at the particle burning temperature Tb.

A control unit (6) estimates an output value of a PM sensor (S2) located at a downstream side of a DPF used as a reference filter, and detects whether the estimated output value exceeds a predetermined value (S3). When the estimated output value exceeds the predetermined value (YES in S3), the control unit detects an output value of the PM sensor (S4), and a heater heats the PM sensor (S5). The control unit detects an output value of the PM sensor (S6) after the PM sensor is heated, and calculates a change ratio of the output values of the PM sensor before and after heating (S7). The control unit estimates an average particle size of PM based on the calculated change ratio (S8), and detects whether the DPF has failed based on a comparison result of a corrected output value of the PM sensor with a threshold value.