METHOD FOR DETECTING FINE DUST IN EXHAUST FUME

Abstract

Procedure that includes the following: Periodic rotation of a sieve (254) of a fine dust sensor (106) via an actuator (304); and Indication of a leakage of a fine dust filter (102) based on a power quantity supplied to the actuator (304).

Description

Area

[0001] The present invention relates generally to a fine dust (FS) sensor. State of the art / Summary

[0002] Engine emission control systems can use various exhaust gas sensors. One example sensor could be a particulate matter sensor that indicates the mass and / or concentration of particulate matter in the exhaust gas. In one example, the particulate matter sensor could operate by monitoring the accumulation of particulate matter over time and providing a reading of the extent of this accumulation as a measure of particulate matter levels.

[0003] Fine dust sensors can correlate a measured change in electrical conductivity (or electrical resistance) between a pair of electrodes placed on the sensor's substrate surface with the amount of fine dust deposited between the electrodes. Fine dust sensors can encounter problems with uneven soot deposition on the sensor due to biasing in the current distribution across the sensor surface. Furthermore, fine dust sensors can be susceptible to contamination from water droplets and / or larger particles present in exhaust gases. This contamination can lead to sensor output errors.

[0004] Other attempts to address the performance of particulate matter sensors involve directing a portion of the exhaust gas toward the sensor. An exemplary approach is shown in US 8,756,913 B2. In this application, a pair of intersecting tubes is arranged along an exhaust duct, with a sensor located in an upper section of the duct and fluidically coupled to an axial tube of the pair. The tubes are designed to collect exhaust gas from a variety of positions within the duct to increase the accuracy of the data provided by the sensor. DE 10 2017 109 389 A1 discloses a particulate matter sensor with a sensor element arranged in a perforated protective tube, but its measurement accuracy is reduced when the exhaust gas flow direction changes.US 8 341 936 B2 discloses an exhaust gas sensor with radially arranged inlet openings for capturing partial flows and guiding them over pressure minima to improve measurement accuracy in the case of inhomogeneous exhaust gas distribution. CN 106 237 745 A relates to bag filter systems with compressed air backflushing, which, however, exhibit high maintenance requirements, increased energy consumption, and safety risks. Systems are known that utilize catalyst heating (DE 10 2016 111 686 A1), valve-based recirculation of residual gases (US 2016 / 0 369 709 A1), or thermodynamically differentiated exhaust gas routing (DE 10 2013 100 065 A1) for emission optimization. However, these known systems have limitations regarding flow characteristics, valve coordination, or flexibility.

[0005] However, the inventors of the present invention have recognized potential problems associated with such systems. For example, the pair of hoses can direct large particulate matter and / or water droplets onto the sensor. This can reduce the reliability of the data provided by the sensor regarding the impairment of the particulate filter.

[0006] In one example, the problems described above can be addressed by a method that involves periodically rotating a fine dust sensor's sieve via an actuator and indicating a fine dust filter leakage based on the amount of power supplied to the actuator. In this way, the amount of power supplied to the actuator increases as the fine dust increases the friction experienced by the sieve during the periodic rotations.

[0007] As an example, the screen is rotated against a filter in the particulate matter sensor at each fixed period interval. The screen is rotated through a threshold angle, with a specific amount of power supplied to the screen being monitored. The screen is then rotated back to its original starting position, and the filter is regenerated to a state containing less particulate matter. This allows the filter in the particulate matter sensor to contain a substantially similar amount of particulate matter after the screen's rotation. The particulate matter sensor is located downstream of a particulate matter filter positioned in the exhaust duct. The particulate matter filter undergoes regeneration to enable it to continue capturing particulate matter. However, after several regeneration events over time, the particulate matter filter can become compromised. This compromise may include one or more cracks, leaks, and holes.This means that a larger quantity of particulate matter can flow to the filter in the particulate matter sensor, thereby increasing the amount of power required to rotate the screen. If this power exceeds a certain threshold, the particulate matter filter in the exhaust duct may be compromised.

[0008] As another example, the particulate matter sensor may not include a filter, either additionally or optionally. However, the sensor is designed to regenerate the filter at fixed intervals as described above. Over time, the particulate matter filter in the exhaust duct becomes compromised. This can lead to higher regeneration temperatures experienced by the filter within the sensor. Therefore, the particulate matter filter in the exhaust duct may be compromised if the regeneration temperature of the filter within the sensor exceeds a certain threshold temperature.

[0009] It will be understood that the foregoing summary is provided to present, in simplified form, a selection of concepts that are described in greater detail in the detailed description. It is not intended to identify important or essential features of the claimed subject matter, the scope of which is defined solely by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages mentioned above or in any part of this disclosure. Brief description of the drawings Fig. Figure 1 shows a schematic diagram of an engine and an associated fine dust (FS) sensor arranged along an exhaust duct. Fig. Figure 2 shows a first embodiment of the FS sensor. Fig. 3A and Fig. Figure 3B shows separated views of a sieve, a filter and a heating element arranged in the first embodiment of the FS sensor. Fig. Figure 4 shows a method for operating the sieve and the heating element and determining an impairment of a fine dust filter located in the exhaust duct. Fig. Figure 5 shows a motor operating sequence illustrating changes in FS sensor conditions over time. Fig. Figure 6 shows a second embodiment of the FS sensor. Fig. Figure 7 shows a method for operating the heating element of the second embodiment and determining an impairment of the fine dust filter based on a regeneration temperature measured in the FS sensor. Fig. Figure 8 shows an engine operating sequence illustrating changes in FS sensor conditions over time. Fig. Figures 2-3 and 6 are shown approximately to scale. Detailed description

[0010] The following description concerns systems and procedures for a particulate matter (PM) sensor. The PM sensor is arranged along an exhaust duct downstream of a particulate filter, as shown in Fig. 1 shown. A first embodiment of the FS sensor is shown in Fig. Figure 2 illustrates the FS sensor, which includes a rotatable sieve and a heating element pressed against opposite surfaces of a filter. The filter is positioned between the sieve and the heating element, as shown in Figure 2. Fig. Figure 3A shows a method for periodically rotating the sieve and measuring the power required to rotate the sieve to a threshold angle. Fig. 4 described. If the power required to rotate the screen to the threshold angle is greater than a threshold power, then the particulate filter in the exhaust duct upstream of the FS sensor may be compromised. An operating sequence illustrating conditions in the FS sensor is described in Fig. 5 shown.

[0011] A second embodiment of the FS sensor is in Fig. Figure 6 illustrates this, wherein the second embodiment includes one or more temperature sensors arranged proximal to the filter in the FS sensor. In one example, there are two temperature sensors, one of which is located upstream of the filter and the other downstream of the filter. A method for comparing feedback from the temperature sensors is shown in Fig. Figure 7 shows that, in one example, the comparison can determine whether a particulate filter in the exhaust duct is impaired. An operating sequence illustrating conditions in the FS sensor is shown in Figure 7. Fig. 8 shown.

[0012] The Fig. Figures 1-3 and 6 show exemplary configurations with a relative positioning of the various components. If such elements are shown as directly touching or directly coupled to one another, then they can be described as directly touching or directly coupled, respectively, in at least one example. Similarly, elements shown as abutting or adjacent to one another can be described as abutting or adjacent to one another in at least one example. As one example, components that are in surface-dividing contact with one another can be described as being in surface-dividing contact. As another example, elements that are positioned separately from one another, with only a space between them and no other components, can be described as such, at least in one example.As a further example, elements shown above / below each other, on opposite sides of each other, or to the left / right of each other can be described as such in relation to one another. Furthermore, as shown in the figures, a topmost element or the highest point of an element can be described as a "top" of the component in at least one example, and a bottommost element or the lowest point of the element as a "bottom" of the component. In the sense used here, top / bottom, upper / lower, and above / below can refer to a vertical axis of the figures and be used to describe the positioning of elements of the figures in relation to one another. Accordingly, elements shown above other elements are, in one example, positioned vertically above the other elements.As a further example, the shapes of the elements shown in the figure may be described as having these shapes (e.g., circular, straight, planar, curved, rounded, chamfered, angled, or the like). Furthermore, elements shown to intersect may, in at least one example, be described as intersecting elements or as intersecting elements. Finally, an element shown inside or outside another element may, in one example, be described as such. It will be understood that one or more components described as "substantially similar and / or identical" may differ from one another depending on manufacturing tolerances (e.g., with a 1-5% deviation).

[0013] Fig. Figure 1 shows a schematic representation of a vehicle system 6. The vehicle system 6 includes an engine system 8. The engine system 8 can include an engine 10 having a plurality of cylinders 30. The engine 10 includes an engine inlet 23 and an engine outlet 25. The engine inlet 23 includes a throttle 62, which is fluidically coupled to the engine intake manifold 44 via an inlet channel 42. The engine outlet 25 includes an exhaust manifold 48, which ultimately leads to an exhaust duct 35 that discharges exhaust gas into the atmosphere. The throttle 62 can be located in the inlet channel 42 downstream of a charging device, such as a turbocharger (not shown), and upstream of an aftercooler (not shown). If present, the aftercooler can be designed to reduce the temperature of the intake air being compressed by the charging device.

[0014] The engine outlet 25 can include one or more emission control devices 70, which may be attached in a short-coupled position within the outlet. One or more emission control devices may include a three-way catalyst, a lean NOx storage catalyst, an SCR catalyst, etc. The engine outlet 25 can also include a particulate filter 102, which temporarily filters FS from incoming gases and is located upstream of the emission control device 70. In one example, the particulate filter 102 is a diesel particulate matter retention system. The particulate filter 102 may have a monolithic structure, made, for example, of cordierite or silicon carbide, with a plurality of internal channels for filtering particulate matter from diesel exhaust.The exhaust gas from the exhaust pipe, which has been filtered after passing through the fine dust filter 102 FS, can be measured in an FS sensor 106 and further processed in the emission control device 70 before being discharged into the atmosphere via the exhaust duct 35. As shown, the FS sensor 106 is located downstream of the fine dust filter 102 in the exhaust duct 35. The FS sensor 106 also includes a filter that is functionally similar to the fine dust filter 102, although the filter in the FS sensor 106 is smaller. In the illustrated example, the FS sensor 106 is a resistive sensor that estimates the filter efficiency of the fine dust filter 102 based on a change in conductivity measured at the electrodes of the FS sensor. A schematic view 200 of the FS sensor 106 is shown in [reference missing]. Fig. 2 shown, as described in more detail below.

[0015] Additionally or alternatively, components of the FS sensor are periodically rotated and / or regenerated in response to operating conditions of the engine and / or exhaust system. These components may include one or more screens and filters. For example, the conditions may include the time elapsed since a previous rotation and / or regeneration, miles driven, estimated particulate matter emissions, etc., as described in more detail below.

[0016] The vehicle system 6 may further include a control system 14. The control system 14 is shown to receive information from a variety of sensors 16 (various examples of which are described here) and to send control signals to a variety of actuators 81 (various examples of which are described here). In one example, the sensors 16 may include an exhaust gas flow rate sensor 126, designed to measure an exhaust gas flow rate through the exhaust duct 35, an exhaust gas sensor (located in the exhaust manifold 48), a temperature sensor 128, a pressure sensor 129 (located downstream of the emission control device 70), and an FS sensor 106. Other sensors, such as additional sensors for pressure, temperature, air-fuel ratio, exhaust gas flow rate, and composition, may be coupled at various points in the vehicle system 6.As a further example, the actuators can include fuel injection devices 66, a throttle 62, particulate filter valves that control filter regeneration (not shown), a motor actuator that controls the FS sensor opening (e.g., control opening of a valve or plate in an inlet of the FS sensor), etc. The control system 14 can include a controller 12. The controller 12 can be designed with computer-readable instructions stored in non-volatile memory. The controller 12 receives signals from the various sensors. Fig. 1. Processes the signals and activates the various actuators. Fig. 1 to adjust the motor operation based on the received signals and instructions stored in a working memory of the controller.

[0017] In one example, the control includes instructions that, when executed, enable the controller to regenerate the filter located in the FS sensor 106. In another example, the controller additionally or alternatively signals an actuator to rotate a screen located in the FS sensor 106 prior to regeneration. The regeneration can occur in response to an elapsed threshold period. The threshold period can be a fixed interval, essentially 10 minutes. The person skilled in the art will recognize that a different duration can be used without infringing upon the scope of protection of this disclosure. By measuring either the power required to rotate the screen or the temperature of the regeneration process in the FS sensor 106, it can be determined whether the fine dust filter 102 is impaired or functioning as intended.Impairment can include the development of one or more cracks, leaks, and holes in the fine dust filter.

[0018] Now, the focus will shift to... Fig. 2 Reference is made to a first embodiment 200 of the FS sensor 106, which is located in the exhaust duct 35. Fig. 1 is arranged. Accordingly, the previously presented components are numbered similarly in the following figures. As described above, the FS sensor 106 is located downstream of a fine dust filter (e.g., fine dust filter 102 made of Fig. 1) arranged. The FS-Sensor 106 is designed to capture and store a portion of the fine dust flowing through the fine dust filter. The FS-Sensor 106 can diagnose the condition of the fine dust filter based on the amount of fine dust captured by the FS-Sensor 106.

[0019] An axis system 290 comprises three axes: an x-axis parallel to the horizontal direction, a y-axis parallel to the vertical direction, and a z-axis perpendicular to both the x- and y-axes. A direction of gravity is represented by arrow 299 and is parallel to the y-axis. A general direction of the exhaust gas flow through the exhaust duct 35 is represented by arrows 298 parallel to the x-axis. A central axis of the exhaust duct 35 and / or exhaust pipe 202 is represented by a dashed line 292. Therefore, the dashed line 292 can be referred to here as the central axis 292.

[0020] The FS sensor 106 can be made of one or more materials, including aluminum, copper, iron, carbon fiber, magnesium, steel, and other materials suitable for an exhaust gas environment. In some examples, surfaces of the FS sensor 106 may be coated to prevent FS from occurring on them. It will be understood that, unless otherwise specified, surfaces of the FS sensor 106 are impermeable to an exhaust gas flow. Thus, there are no additional inlets or other outlets besides those described herein. In one example, the FS sensor 106 of a vehicle with its wheels on the ground is coupled to the top of the exhaust pipe 202 that is furthest from the ground.

[0021] The first embodiment 200 of the FS sensor 106 is shown as a substantially U-shaped tube. In one example, the FS sensor 106 is asymmetrical, with an upstream tube 222 being longer along the y-axis than a downstream tube 232. It will be understood that the properties described herein as upstream or downstream are described with respect to the direction of the exhaust gas flow. Accordingly, exhaust gas reaches the upstream tube 222 before the downstream tube 232. As shown, the upstream tube 222 extends into the exhaust duct 35 to a location below the central axis 292 along the y-axis. The downstream tube 232, however, extends into the exhaust duct 35 to a location above the central axis 292 along the y-axis. In some examples, the upstream pipe 222 and the downstream pipe 232 may additionally or optionally have an essentially equal height (e.g., a length along the y-axis).Additionally or alternatively, the FS sensor 106 can have other shapes without deviating from the scope of protection of this disclosure. For example, the FS sensor 106 can have a C-shape, V-shape, and J-shape.

[0022] A connecting pipe 242 is physically coupled to the upstream pipe 222 and the downstream pipe 232. Specifically, the connecting pipe 242 is physically coupled to the upstream pipe 222 at an upstream bend 244. Likewise, the connecting pipe 242 is physically coupled to the downstream pipe 232 at a downstream bend 246. The connecting pipe 242 can be physically coupled to the upstream pipe 222 and the downstream pipe 232 by fusible connections, welds, adhesives, and / or a combination thereof. The connecting pipe 242 is parallel to the x-axis and perpendicular to the upstream pipe 222 and the downstream pipe 232.

[0023] The connecting pipe 242, the upstream bend 244, and the downstream bend 246 are located entirely outside the exhaust pipe 202. The upstream pipe 222 extends from the upstream bend 244, through a cutout in the exhaust pipe 202, and into the exhaust duct 35 to a depth below the central axis 292. Welds, fusion bonds, adhesives, or a combination thereof can physically couple the upstream pipe to the exhaust pipe 202. These coupling elements also hermetically seal an interface between the upstream pipe 222 and the exhaust pipe 202, preventing exhaust gas from escaping through the interface into the ambient atmosphere and / or to the engine. The downstream pipe 232 extends from the downstream bend 246, through a cutout in the exhaust pipe 202 and into the exhaust duct 35 to a depth above the central axis 292.Welds, fusion joints, adhesives, or a combination thereof can physically couple the downstream pipe 232 to the exhaust pipe 202. These coupling elements also hermetically seal the interface between the downstream pipe 232 and the exhaust pipe 202, preventing exhaust gas from flowing through the interface to the engine and into the ambient atmosphere. In this way, exhaust gas flows only through one tailpipe from the exhaust duct 35 into the ambient atmosphere.

[0024] The diameter of the exhaust pipe 202 is larger than the diameters of the upstream pipe 222, the downstream pipe 232, and the connecting pipe 242. The diameters of the upstream pipe 222, the downstream pipe 232, and the connecting pipe 242 can be essentially the same, so that the FS sensor 106 has a single diameter. It will be understood that the diameters of the pipes of the FS sensor 106 can be unequal without deviating from the scope of protection of this disclosure. In this way, the FS sensor 106 can be a single, integrated device.

[0025] The upstream pipe 222 comprises a plurality of perforations 224 designed to allow exhaust gas to flow into a first channel located within the upstream pipe 222. The perforations 224 are oriented upstream in a direction opposite to the direction of the incoming exhaust gas flow. Thus, exhaust gas can flow continuously through the perforations 224 and into the first channel of the upstream pipe 222. The perforations 224 are arranged along a common axis that is parallel to a central axis 284 of the upstream pipe 222. In one example, there are exactly five perforations. However, it will be understood that there can be more or fewer than five perforations 224 without deviating from the scope of protection of this disclosure.For example, the opening of the perforations 224 can be reduced to accommodate a larger number of perforations 224 on the upstream side of the upstream pipe 222. In one example, the perforations 224 are elliptical. However, the perforations 224 can have other shapes, such as square, circular, rectangular, or triangular, without deviating from the scope of protection of this disclosure. In one example, the perforations 224 are the only element of the first pipe 222 that couples an interior of the first pipe 222 to the exhaust duct 35.

[0026] The first channel of the upstream pipe 222 is designed to receive exhaust gas from the exhaust duct 35 and direct the exhaust gas in a direction opposite to gravity 299 towards the connecting pipe 242, outside the exhaust duct. However, the first channel of the upstream pipe 222 is also designed to prevent a flow of large particles (e.g., water droplets and / or large particulate matter) to the connecting pipe 242. Large particles can distort the measurements of the FS sensor 106. Several factors can limit the flow of large particles to the connecting pipe 242. First, gravity pushes the large particles downwards away from the connecting pipe 242.Secondly, the distance between the upstream surface, where the perforations 224 are arranged, and the downstream surface of the upstream pipe 222 is dimensioned such that a momentum of large particles transports the large particles into the downstream surface. Thus, large particles can impact the downstream surface and therefore do not flow into the connecting pipe 242. In embodiment 200, the first pipe 222 is sealed at a lower surface 226. In this way, large particles can accumulate on the underside of the first pipe 222 and burn off when the exhaust gas temperatures are sufficiently hot (e.g., higher than 600 °C). However, it will be understood that in alternative embodiments, the lower surface 226 may include an opening for diverting large particles from the first channel of the upstream pipe 222.

[0027] The connecting pipe 242 includes a second channel designed to receive exhaust gas from the first channel of the upstream pipe 222. Exhaust gas flows through the second channel of the connecting pipe 242 in a direction substantially parallel to the direction of the incoming exhaust gas flow. However, the exhaust gas in the second channel of the connecting pipe flows outside of the exhaust gas channel 35, separate from the exhaust gas in the exhaust gas channel 35.

[0028] A sieve 254, a filter 256, and a heating element 258 are arranged cascading along a horizontal axis 282 of the second channel of the connecting pipe 242. In one example, the horizontal axis 282 is a central axis of the connecting pipe 242 and is parallel to the central axis 292 of the exhaust pipe 202. The sieve 254 is arranged upstream of the filter 256, which is arranged upstream of the heating element 258. The sieve 254 is in surface-sharing contact with the filter 256, and the filter 256 is in surface-sharing contact with the heating element 258. In this way, the filter 256 is arranged between the sieve 254 and the heating element 258.

[0029] The screen 254 is porous and designed to allow exhaust gas to flow directly through it to the filter 256. The screen 254 is not capable of trapping FS in the exhaust gas stream. Therefore, particles do not accumulate on any surface of the screen 254. In one example, the screen is a wire mesh. However, in alternative embodiments, the screen 254 can be corrugated or have other similar shapes.

[0030] In one example, the filter 256 is honeycomb-shaped to allow exhaust gas to flow through it while also being designed to capture FS (free-running particles) in the exhaust gas stream. Accordingly, particles accumulate on surfaces of the filter 256. Particles deposited on the filter 256 can contact surfaces of the screen 254. The screen 254 is designed to rotate about the horizontal axis 282 at a threshold angle during certain operating conditions. The FS deposited on the filter 256 can increase the frictional forces applied to the screen 254, with the power required to rotate the screen 254 into a desired position being proportional to the amount of FS deposited on the filter 256. In one example, the power can be electrical, mechanical (e.g., hydraulic), and / or a combination thereof. Therefore, if the power required to rotate the sieve to the threshold angle increases, then the amount of FS deposited on the filter 256 also increases.In some examples, the sieve 254 is rotated based on a fixed period interval (e.g., every 10 minutes of accumulated motor operation) to measure the amount of FS deposited on the filter 256. Following the rotation of the sieve 254, the heating element 258 is activated to burn off the FS deposited on the filter 256. In this way, the filter 256 is reset to a less loaded state, designed to capture more FS. This is described below in relation to... Fig. 4 described in detail.

[0031] Exhaust gas flows from the second channel of the connecting pipe 242 to a third channel of the downstream pipe 232. The exhaust gas re-enters the boundaries of the exhaust pipe 202 and flows out of the downstream pipe 232 via the outlet 234. In this way, the downstream pipe 232 is open at one end proximal to the central axis 292 via the outlet 234.

[0032] In particular, the curved arrows 272 indicate a direction of the exhaust gas flow relative to the FS sensor 106. Additionally, the circles 288 indicate a direction of the flow of large particles and / or water droplets relative to the FS sensor 106. As shown, exhaust gas and large particles and / or water droplets enter the upstream pipe 222 through the perforations 224 in a direction that is essentially parallel to the central axis 292. Larger particles and / or water droplets continue to flow in a direction that is essentially parallel to the central axis 292 and impinge on a downstream surface of the upstream pipe 222.In some examples, the upstream pipe 222 includes an opening similar to the outlet 234 of the downstream pipe 232, allowing larger particles and / or water droplets from the underside of the upstream pipe 222 below the central axis 292 to flow out through the opening and re-enter the exhaust duct 35. This prevents larger particles and / or water droplets from impacting the exhaust duct.

[0033] The exhaust gas rotates after entering the first channel of the upstream pipe 222 and flows in a direction opposite to gravity 299, parallel to an upstream vertical axis 284. In one example, the upstream vertical axis 284 is a central axis of the upstream pipe 222. The exhaust gas flows from a boundary of the exhaust pipe 202 and flows into the second channel of the connecting pipe 242. Specifically, the exhaust gas rotates after exiting a boundary of the exhaust pipe 202 and flows in a direction parallel to the horizontal axis 282, which is parallel to the central axis 292 of the exhaust channel 35. In this way, the exhaust gas in the exhaust channel 35 and the exhaust gas in the connecting pipe 242 flow in substantially parallel directions. As shown, the upstream vertical axis 284 is essentially perpendicular to the horizontal axis 282.Thus, the exhaust gas essentially rotates by 90 degrees as it flows from the upstream pipe 222 to the connecting pipe 242.

[0034] The exhaust gas flows through the sieve 254, the filter 256, and the heating element 258 before flowing to the downstream pipe 232. The filter 256 is designed to collect free radicals (FS) from the exhaust gas flowing through it. Therefore, the exhaust gas upstream of the filter 256 contains more free radicals than the exhaust gas downstream of the filter 256.

[0035] The exhaust gas in the downstream pipe 232 flows with gravity 299 in a direction that is essentially parallel to a downstream vertical axis 286. In one example, the downstream vertical axis 286 is a central axis of the downstream pipe 232. Additionally, the downstream vertical axis 286 is parallel to the upstream vertical axis 284 and perpendicular to the central axis 292 and the horizontal axis 282. Thus, the exhaust gas rotates by essentially 90 degrees as it flows from the connecting pipe 242 to the downstream pipe 232. The exhaust gas exits the FS sensor 106 by exiting the downstream pipe 232 through the outlet 234. The exhaust gas rotates essentially 90 degrees as it flows through the outlet 234 and mixes with the exhaust gas in the exhaust channel 35. In this way, the exhaust gas flow through the FS sensor in the embodiment from Fig. 2 106 essentially U-shaped.

[0036] Now, the focus will shift to... Fig. Reference is made to Figure 3A, which shows an exploded view 300 of the sieve 254, the filter 256, and the heating element 258 separately. The sieve 254, the filter 256, and the heating element 258 are arranged along the horizontal axis 282 of the connecting tube (e.g., the connecting tube 242 made of Fig. 2) arranged in a cascading fashion.

[0037] The sieve 254 is cylindrical with an upstream surface 312, a downstream surface 314, and an outer annular surface 316. The upstream surface 312 faces a direction opposite to the direction of the incoming exhaust gas flow. The downstream surface 314 faces the filter 256 and is pressed against the filter 256 when the FS sensor (e.g., the FS sensor 106 from the Fig. 1 and Fig. 2) is fully assembled. The outer ring surface 316 is in surface-sharing contact with an inner surface of the connecting pipe and is physically coupled to it. In this way, all the exhaust gas flowing through the connecting channel passes through the screen 254.

[0038] An actuator 304, including a rotating shaft 306, is coupled to the screen 254. Specifically, the rotating shaft 306 is physically coupled to the actuator 304 and the screen 254 at opposite ends. The rotating shaft 306 is designed to rotate the screen 254 based on the power supplied by the actuator 304 in response to instructions from a controller 12. Specifically, the rotating shaft 306 rotates the screen 254 about the horizontal axis 282 by a threshold angle, as described in more detail with reference to Fig. 3B is described. The actuator 304 can be electrical, mechanical, or a combination of both.

[0039] The filter 256 is cylindrical with an upstream surface 322, a downstream surface 324, and an outer annular surface 326. In one example, the filter 256 has a similar size (e.g., substantially the same diameter and width) as the screen 254. Alternatively, the filter 256 and the screen 254 have different sizes without deviating from the scope of protection of this disclosure. For example, the filter 256 is larger than the screen 254. The upstream surface 322 faces the screen 254 and is in surface-sharing contact with the downstream surface 314 when the FS sensor (e.g., the FS sensor 106) is activated. Fig. 2) is fully assembled. The downstream surface 324 faces the heating element 258 and is in surface-sharing contact with the heating element when the FS sensor is fully assembled. The heating element is designed to heat up in response to instructions from the controller 12. FS on the filter 256 can begin to burn at a threshold temperature (e.g., higher than or equal to 600 °C). Thus, the filter 256 can return to a less loaded state when FS is burned off and drawn through the connecting pipe as exhaust gas flows through it. In this way, the filter 256 returns to a state designed to capture more FS than the FS that is burned off from the filter 256 by means of the heating element 258.

[0040] Now, the focus will shift to... Fig. Reference is made to Figure 3B, which shows a view 350 in an upstream-downstream direction along the horizontal axis 282 in the direction of the screen 254. The solid line 352 shows an initial position of the rotating shaft (e.g., the rotating shaft 306 from Fig. 3A). The dashed line 354 indicates a final position of the rotating shaft after a rotation of the sieve 254. An angle α represents a threshold angle and lies between 2 and 15 degrees. In one example, the angle α (e.g., threshold angle) corresponds to exactly five degrees. After the sieve 254 has been rotated clockwise to its final position, it is rotated counterclockwise and returns to its initial position.

[0041] In one example, the amount of power (e.g., voltage) required to rotate the screen 254 clockwise from its initial position to its final position is monitored. This amount of power may be proportional to the amount of FS deposited on the filter 256. This can be due to the FS increasing the frictional forces between the filter 256 and the screen 254. If the amount of power required to rotate the screen through the threshold angle is greater than a threshold power level, then the particulate filter in the exhaust duct upstream of the FS sensor may be compromised. This is described in more detail below.

[0042] Now, the focus will shift to... Fig. Reference is made to a method 400 for rotating the sieve and diagnosing a condition of a particulate filter in an exhaust duct.

[0043] Instructions for performing procedure 400 and the other procedures included herein may be executed by a controller based on instructions stored in a memory of the controller and in conjunction with signals received from sensors of the motor system, such as those referred to above. Fig. 1. Sensors described. The controller can use motor actuators of the motor system to adjust the motor operation according to the procedures described below.

[0044] Previously introduced components can be integrated into the description of the process 400 described herein. For example, the sieve 254, the filter 256, the heating element 258, the FS sensor 106, the fine dust filter 104, the actuator 304, the rotary shaft 306, and the control unit 12 from the Fig. 1, Fig. 2 and Fig. 3A.

[0045] Procedure 400 can begin at 402, where Procedure 400 involves determining, estimating, and measuring the current engine operating parameters. Current engine operating parameters may include one or more from engine speed, engine temperature, vehicle speed, manifold pressure, EGR flow rate, throttle position, ambient temperature, and air / fuel ratio.

[0046] In procedure 404, step 400 involves determining the time elapsed since a previous rotation of the sieve. In one example, the elapsed time is independent of the vehicle operating parameters. Therefore, the elapsed time can include periods with the engine and / or vehicle off. Alternatively, the elapsed time can track periods with the engine running and particulate matter emitted from the engine. Therefore, the elapsed time cannot monitor events with the engine and / or vehicle off. Additionally or alternatively, the elapsed time can exclude cold starts. Particulate matter released during a cold start period can be significantly higher than particulate matter released from engine operation at a desired engine temperature for a similar period.

[0047] In one example, the particulate filter and the FS sensor capture particulate matter when a vehicle is switched on and a cold start occurs. Based on the engine temperature being higher than or equal to the desired operating temperature (e.g., 185-210 °C), the cold start is determined to be complete. The control unit can then signal the heating element in the FS sensor to regenerate the filter. After the filter in the FS sensor has regenerated following the cold start, the control unit can begin measuring the elapsed time to determine when the screen in the FS sensor should be rotated.

[0048] In procedure 406, the process involves determining whether the elapsed time is greater than or equal to a threshold interval. In one example, the threshold interval is based on a fixed period interval. For instance, the threshold interval is exactly 10 minutes. Additionally or alternatively, the threshold interval may be based on a number of miles (e.g., 5 miles) traveled since a previous rotation. Additionally or alternatively, the threshold interval may be based on an estimate of the particulate matter released to the FS sensor, with the threshold interval being reached when the estimate substantially matches a threshold particulate matter release. In one example, the threshold particulate matter release is based on the amount of particulate matter released to the FS sensor from an unobstructed particulate filter while an engine is running at the desired operating temperature.

[0049] If the elapsed time is less than the threshold interval, the process switches from 400 to 408 to maintain the current motor operating parameters and does not rotate the sieve. Therefore, no power is supplied to the actuator and the heating element is not activated. The elapsed time continues to be measured.

[0050] If the time is greater than or equal to the threshold interval, then Method 400 transitions to 410 to signal the actuator to operate the rotary shaft to rotate the screen by a threshold angle. The threshold angle can be a range between 2 and 30 degrees. In one example, the threshold angle is exactly 5 degrees. As described above, the threshold angle (e.g., α) is measured clockwise from an initial position of the screen. In the example of Method 400 described herein, the actuator is an electrical actuator, and a voltage required to rotate the screen is measured. However, the actuator can be a mechanical actuator, and a force required to rotate the screen can be measured without infringing upon the scope of protection of this disclosure.

[0051] In procedure 412, the process involves measuring the voltage required to rotate the screen through the threshold angle. This voltage can vary based on the amount of particulate matter deposited on the filter. For example, if the particulate matter load on the filter increases, the voltage required to rotate the screen through the threshold angle also increases. Similarly, if the particulate matter load on the filter decreases, the voltage required to rotate the screen through the threshold angle decreases. Thus, if more particulate matter has passed through the particulate filter into the exhaust duct and is flowing towards the filter in the FS sensor, the voltage required to rotate the screen will increase.

[0052] In case 414, the procedure involves 400 turns of the sieve back to its starting position. This involves turning the sieve clockwise by an amount opposite to the threshold angle. For example, if the threshold angle is 5°, then after measuring the required voltage, the sieve is turned by -5°.

[0053] In procedure 416, step 400 involves determining whether the measured voltage is less than a threshold voltage. The threshold voltage is the voltage required to rotate the screen through the threshold angle when the particulate filter upstream of the FS sensor has a leak. When rotating the screen, provided the particulate sensor does not leak, the voltage required to rotate the screen is less than the threshold voltage. However, when the particulate filter begins to leak and the filter in the FS sensor captures an increased amount of FS, the voltage increases to the threshold voltage. In other words, a sufficient amount of particulate matter escapes from the compromised particulate filter beyond the threshold interval for the voltage required to rotate the screen to exceed the threshold voltage.

[0054] As an example, in a particulate filter in an exhaust duct upstream of the particulate filter sensor, a relatively small amount of particulate matter (PF) can flow through the PF filter and into the filter within the PF sensor. The screen is rotated periodically based on a fixed interval, with the voltage required to rotate the screen to the threshold angle remaining essentially constant. For example, if the PF filter has no leaks, the voltage required to rotate the screen to the threshold angle is essentially a lower threshold voltage (e.g., 5 V). Over time, leaks or cracks can develop in the PF filter due to high exhaust gas and / or regeneration temperatures, causing a larger amount of PF to escape through the particulate filter. Consequently, the voltage required to rotate the screen around the threshold angle increases to an upper threshold voltage (e.g., 7.5 V).In one example, the voltage required to rotate the screen around the threshold angle when the particulate filter has a leak is exactly 1.5 times greater than the voltage required when the particulate filter does not leak. Thus, the increased particulate matter load on the filter in the particulate matter sensor increases the resistance (e.g., friction) that the screen experiences as it rotates toward the threshold angle.

[0055] If the voltage is greater than or equal to the threshold voltage, then procedure 400 proceeds to 418 to indicate that the particulate filter in the exhaust duct upstream of the FS sensor is compromised, the compromise being a crack, leak, and / or hole. At 420, procedure 400 further includes activating a warning light to alert a driver to the compromise. This may involve setting a diagnostic code and / or providing a message or illumination to a driver via a display in a vehicle in which the FS sensor is installed. For example, the message may be sent to the vehicle's navigation screen. Additionally or alternatively, procedure 400 may further include adjusting one or more operating parameters to reduce particulate emissions.This may include one or more of the following: increasing the EGR flow, increasing the air / fuel mixture, decreasing the fuel injection volume and / or pressure, and increasing the water injections into the cylinder.

[0056] In any case, procedure 400 transitions to 420, or, after determining that the measured voltage is less than the threshold voltage, to 422 at 416. At 422, procedure 400 involves activating the heating element for a threshold regeneration period. Activating the heating element resets the filter in the FS sensor to a less loaded state. In other words, the FS burns off from the filter, and the amount of FS on the filter decreases. In this way, after each rotation of the screen, the FS load is reset to a relatively low and / or zero FS condition.

[0057] In procedure 424, step 400 involves determining whether the threshold regeneration period is complete. The threshold regeneration period can be based on the time required, for a non-leaking particulate filter, to burn off a quantity of FS that has accumulated on the filter in the FS sensor between screen rotations. In one example, the threshold regeneration period is based on a threshold time (e.g., 30 seconds). Alternatively, the threshold regeneration period is based on a threshold distance (e.g., one mile). In some examples, the threshold regeneration period is based on a temperature measured downstream of the filter in the connecting pipe, where, if the temperature is below a threshold regeneration temperature (e.g., below 600 °C), then threshold regeneration is complete.If the threshold regeneration period is not completed, then procedure 400 switches to 426 to keep the heating element switched on and continues to monitor the regeneration period.

[0058] Once the threshold regeneration period is complete, procedure 400 transitions to 428 to deactivate the heating element. This allows FS to accumulate in the filter within the FS sensor without causing it to burn out. At step 430, procedure 400 begins monitoring the time between rotations. This ensures that the filter within the FS sensor has access to the entire threshold interval to capture FS before the subsequent rotation of the screen.

[0059] Now, the focus will shift to... Fig. Reference is made to Figure 5, which shows a sequence 500 illustrating periodically defined rotations of the sieve and regenerations of the filter in the FS sensor. In one example, the operating sequence 500 is a graphical representation of procedure 400 from Figure 5. Fig. 4, which is in the vehicle system 6 from Fig. 1 is implemented. Curve 510 represents a condition of the heating element that can be set between ON and OFF positions. Curve 520 represents an FS sensor filter load, and curve 522 represents a threshold FS sensor filter load. In one example, the threshold FS sensor filter load is based on the amount of FS that has accumulated on the FS sensor filter when the particulate filter in the exhaust duct is compromised (e.g., has a leak).Curve 530 represents a voltage required to rotate the screen through the threshold angle; curve 532 represents a lower threshold voltage, essentially an average voltage required to rotate the screen when the particulate filter in the exhaust duct is leak-free; and curve 534 represents an upper threshold voltage, essentially a voltage required to rotate the screen when the particulate filter in the exhaust duct is leaking. In some examples, the lower and upper threshold voltages can be adjusted based on engine operating parameters. For example, the lower and upper threshold voltages can be similarly increased when an engine temperature is below an ambient temperature (e.g., during a cold start). The upper threshold voltage can be 1.5 to 3 times greater than the lower threshold voltage.In one example, the upper threshold voltage is exactly 1.5 times the lower threshold voltage. For example, if the lower threshold voltage is 10 V, then the upper threshold voltage is 15 V. Time increases from the left to the right side of the figure.

[0060] Before t1, the heating element is switched off (graph 510) and the voltage (graph 530) is lower than the lower threshold voltage (graph 532). In particular, the voltage is essentially 0 and the screen is not rotating. It will be understood that when graph 530 is masked by graph 500, the voltage is essentially 0. The FS sensor filter load (graph 520) increases towards the threshold FS sensor filter load (graph 522) as exhaust gas flows from a section of the exhaust duct downstream of a particulate filter to the FS sensor filter. At t1, a time since a previous screen rotation is greater than or equal to a threshold interval. Therefore, power (e.g., electricity) is supplied to the actuator to rotate the screen. The FS sensor filter load continues to increase and the heating element remains switched off.

[0061] After t1 and before t2, the voltage continues to decrease towards the lower threshold voltage. The FS sensor filter load continues to increase, and the heating element remains inactive. At t2, the screen has rotated by the threshold angle, and the voltage is slightly lower than the lower threshold voltage. This confirms that the particulate filter in the exhaust duct is functioning as intended and is not compromised. The screen returns to its initial position and stops rotating. Consequently, the voltage to the actuator connected to the screen is reduced to zero. The heating element is then activated.

[0062] After t2 and before t3, the heating element remains active, and the FS sensor filter load begins to decrease to a relatively low level as the FS regenerates from the filter. At t3, the threshold regeneration period is complete, and the heating element is deactivated. Thus, regeneration ends when the heating element is deactivated. In some examples, regeneration can continue after the heating element is deactivated. In such cases, self-burning occurs, and the FS load on the filter continues to decrease.

[0063] After t3 and before t4, the FS sensor filter load increases as exhaust gas containing FS flows through the FS sensor. At t4, the threshold interval between rotations is reached, and the screen begins to rotate. Therefore, power is supplied to the actuator to rotate the screen. The FS sensor filter load continues to increase.

[0064] After t4 and before t5, the voltage increases to a level greater than the lower threshold voltage when the screen is rotated towards the threshold angle. The FS sensor filter load continues to increase. The heating element remains deactivated. At t5, the screen has been rotated to an angle essentially equal to the threshold angle. The required voltage is greater than the lower threshold voltage but less than the upper threshold voltage. Therefore, the particulate filter in the exhaust duct upstream of the FS sensor is not affected. The screen returns to its initial position before rotation, and the heating element is activated.

[0065] After t5 and before t6, the heating element remains switched on, and the FS sensor filter load continues to decrease. At t6, the threshold regeneration period is fulfilled, and the heating element is deactivated. In one example, the threshold regeneration period is fixed and the same for each FS sensor filter regeneration. This makes the threshold regeneration period independent of the FS sensor filter load. The FS sensor filter load is reduced to a relatively low level, similar to the FS load at t3. Thus, after each FS sensor filter regeneration, the heating element returns the filter to a similar condition.

[0066] In another example, the threshold regeneration period from t5 to t6 is longer than the threshold regeneration period between t2 and t3. This can be attributed to the fact that the FS sensor filter load is greater at t5 than at t2, which can be determined by the voltage required to rotate the filter. In other words, the threshold regeneration period can be proportional to the voltage required to rotate the filter to the threshold angle. Thus, the threshold regeneration also increases as the required voltage decreases.

[0067] After t6 and before t7, the load on the FS sensor filter begins to increase from a relatively low load towards the threshold load. At t7, the filter starts to rotate and the actuator coupled to the filter receives power.

[0068] After t7 and before t8, the screen continues to rotate. The FS sensor filter load continues to increase, rising to a level greater than the threshold FS sensor filter load. As described above, the threshold FS sensor filter load corresponds to a quantity of FS that generates sufficient friction such that the voltage required to rotate the screen to the threshold angle exceeds the upper threshold voltage. At t8, the screen reaches the threshold angle, and the voltage required to rotate the screen exceeds the upper threshold voltage. Consequently, it is determined that the particulate filter in the exhaust duct upstream of the FS sensor is compromised, with the compromise involving one or more components being damaged by a leak or crack. Therefore, a warning light is applied and a warning indicator is activated to alert the driver to the compromised particulate filter.No more power is supplied to the actuator connected to the sieve. The heating element is activated.

[0069] After ts and before t9, the heating element continues to regenerate the particulate filter (PF). In some examples, one or more engine operating parameters can be adjusted to reduce the PF output from the engine, given the particulate filter's impairment. For example, the EGR flow rate to the engine can increase in response to the particulate filter's impairment. Additionally or alternatively, the amount of fuel injected into one or more of the engine cylinders can be reduced (e.g., the air / fuel ratio can be increased). At t9, the threshold regeneration period is reached, and the heating element is deactivated. After t9, the PF load continues to increase.

[0070] Now, the focus will shift to... Fig. 6 Reference is made to a second embodiment 600 of the FS sensor 106 made of Fig. Figure 1 shows. In one example, the second embodiment 600 is similar to the one in Fig. The first embodiment 200 is shown in Figure 2. In particular, the second embodiment 600 comprises the upstream pipe 222, the perforations 224, the downstream pipe 232, the outlet 234, the connecting pipe 242, the filter 256, and the heating element 258, which are shown in the first embodiment 200. Furthermore, the second embodiment 600 can be arranged in a similar section of the exhaust duct 35 as the first embodiment 200. In addition, the exhaust gas flow through the second embodiment 600 is essentially similar to the exhaust gas flow through the first embodiment 200.

[0071] However, the second embodiment 600 differs from the first embodiment 200 in that it does not have a sieve (e.g. the sieve 254 made of Fig. 2) includes. Thus, the second embodiment 600 also does not include the actuators for rotating the sieve described above. The second embodiment 600 further comprises a first sensor 612 and a second sensor 614, which are not shown in the first embodiment 200.

[0072] In this example, the first sensor 612 and the second sensor 614 are temperature sensors. Here, the first sensor 612 is referred to as the first temperature sensor 614. Similarly, the second sensor 614 is referred to as the second temperature sensor 614. The first temperature sensor 612 is located upstream of the second temperature sensor 614 relative to the direction of the exhaust gas flow. The filter 256 and the heating element 258 are positioned between the first 612 and the second 614 temperature sensors. Thus, the first temperature sensor 612 measures the temperature of the exhaust gas in the FS sensor 106 upstream of the filter 256. Additionally, the second temperature sensor 614 measures the temperature of the exhaust gas in the FS sensor 106 downstream of the filter 256 and the heating element 258.Control 12 includes instructions that, when executed, allow the controller to determine a temperature change across filter 256 based on feedback from the first 612 and the second 614 temperature sensors. In one example, the temperature change is measured only when the heating element is activated. The heating element can be activated based on a fixed period interval, as described in more detail below.

[0073] In some examples, the first embodiment 200 and the second embodiment 600 can be additionally or alternatively combined such that the FS sensor includes the rotatable screen and the temperature sensors. In such an embodiment, a routine for diagnosing a particulate filter in an exhaust duct upstream of the FS sensor can involve monitoring the power required to rotate the screen by the threshold angle and measuring a temperature change across the FS sensor's filter. In one example, if the required power is greater than a threshold power or if the temperature change is greater than the threshold temperature change, then the particulate filter in the exhaust duct is compromised.

[0074] Now, the focus will shift to... Fig. Reference is made to a method 700 for periodically regenerating the filter and measuring a temperature change of the exhaust gas above the filter in response to the regeneration. In one example, the method 700 can be carried out with respect to the second embodiment 600 of the FS sensor 106.

[0075] In some examples, method 700 can be implemented in conjunction with method 400, as described above. In particular, in an embodiment that incorporates features of the first 200 and second 600 embodiments, method 700 can begin after the sieve has been rotated from the threshold angle position back to its initial position (e.g., frame 414). In such an example, method 700 can begin at 710.

[0076] Procedure 700 can begin at 702, where Procedure 700 involves determining, estimating, and measuring the current engine operating parameters. Current engine operating parameters may include one or more from engine speed, engine temperature, vehicle speed, manifold pressure, EGR flow rate, throttle position, ambient temperature, and air / fuel ratio.

[0077] In procedure 704, step 700 involves determining the time elapsed since a previous filter regeneration. This elapsed time is measured from the completion of the previous regeneration. The elapsed time is essentially the same as the time elapsed, and its measurement is similar to the measurement described above in step 404.

[0078] In the 706, the procedure involves determining whether the elapsed time is greater than or equal to a threshold interval. In one example, the threshold interval is based on a fixed period interval. For instance, the threshold interval is exactly 10 minutes. Additionally or alternatively, the threshold interval can be based on a number of miles (e.g., 5 miles) traveled since a previous regeneration.

[0079] If the elapsed time is less than the threshold interval, the process transitions from 700 to 708 to maintain the current engine operating parameters and does not regenerate the filter. Therefore, the heating element is not activated. If the time is greater than or equal to the threshold interval, the process transitions from 700 to 710 to signal the heating element to heat the filter. Therefore, the heating element is activated when the filter temperature increases. In one example, the filter temperature rises to at least a threshold regeneration temperature (e.g., 600 °C). This allows any residual fuel (FS) deposited on the filter to begin burning, resulting in hotter exhaust gas downstream of the filter compared to upstream.

[0080] In procedure 700, 712 involves measuring exhaust gas temperatures upstream and downstream of the filter in the FS sensor. The first temperature sensor 612 measures an exhaust gas temperature upstream of the filter, and the second temperature sensor 614 measures an exhaust gas temperature downstream of the filter. It will be understood that a temperature measured by the second temperature sensor is higher than a temperature measured by the first temperature sensor. In one example, the measurement of the exhaust gas temperature after activation of the heating element may be delayed for a threshold time (e.g., 15 seconds after activation of the heating element). Additionally or alternatively, temperatures from the first and second temperature sensors may be measured during the entire heating of the filter, and the largest temperature difference between the first and second temperature sensors may be used in a remaining part of procedure 700.

[0081] In procedure 700, 714 involves determining whether a temperature difference between the first and second temperature sensors is less than a threshold temperature difference and / or a threshold temperature change. The threshold temperature difference is based on a temperature difference between the sensors when the particulate filter in the exhaust duct upstream of the FS sensor has a leak. The threshold temperature difference is greater than an average temperature difference between the first and second temperature sensors when the particulate filter does not have a leak. In one example, the threshold temperature difference is exactly 1.5 times the average temperature difference. Other values ​​between the threshold temperature difference and the average temperature difference have been implemented.

[0082] In other words, the filter in the FS sensor regenerates at a first temperature, where the first temperature is a regeneration temperature based on the amount of particulate matter captured by the filter after the threshold interval. If the particulate filter in the exhaust duct is compromised, then the amount of particulate matter captured by the filter during the threshold interval is greater than the amount captured when the particulate filter is not compromised. Therefore, if the particulate filter is compromised, the filter in the FS sensor regenerates at a second temperature, which can be higher than the first temperature. If the temperature difference between the feedback from the first temperature sensor 612 and the second temperature sensor 614 is greater than the threshold change (e.g., regeneration occurs too hot because too much particulate matter is being combusted), then the particulate filter is compromised.

[0083] If the temperature difference is greater than the threshold temperature difference, the procedure transitions from 700 to 716 to indicate that the particulate filter in the exhaust duct is impaired. At 718, a warning light is activated to signal to the driver that maintenance is required.

[0084] In any case, procedure 700 proceeds to 718, or, after determining that the threshold change is less than the threshold temperature change, to 720, in order to continue heating the filter.

[0085] In procedure 700, 722 involves determining whether the threshold regeneration period is complete. The threshold regeneration period in 722 is similar to the threshold regeneration period described above for procedure 400 in procedure 424.

[0086] If the threshold regeneration period is not complete, the procedure proceeds to 724 to continue monitoring the regeneration period. If the threshold regeneration period is complete, the procedure proceeds to 726 to deactivate the heating element. After the heating element is deactivated, procedure 700 begins at 728 to monitor the time between regenerations.

[0087] In an alternative embodiment, where an FS sensor comprises both the screen and the temperature sensors described above, a method may involve rotating the screen and subsequently measuring a temperature change across the filter during regeneration. Accordingly, the method may involve monitoring the time elapsed between rotations of the screen, rotating the screen when the elapsed time is substantially equal to a threshold interval. The screen is rotated to the threshold angle and then returned to its initial position. The amount of power required to rotate the screen to the threshold angle is measured. After the screen returns to its initial position, the heating element is activated, and the exhaust gas temperatures upstream and downstream of the filter are measured.

[0088] For example, if both the power required to rotate the screen exceeds a threshold power and the temperature change across the filter exceeds a threshold temperature change, then the particulate matter sensor located in the exhaust duct is determined to be malfunctioning. Additionally or alternatively, if only one of these conditions is met—either the power required to rotate the screen exceeds the threshold power or the temperature change across the filter exceeds the threshold temperature change—then the particulate matter filter in the exhaust duct is determined to be malfunctioning.In some examples, it is not determined that the particulate filter in the exhaust duct is impaired if only one or both of the following occur: that the power required to rotate the screen is less than a threshold power and the temperature change across the filter is less than a threshold temperature change.

[0089] Now, the focus will shift to... Fig. Reference is made to Figure 8, which shows an operating sequence 800 illustrating periodically defined regenerations of the filter in the FS sensor. In one example, operating sequence 800 is a graphical representation of procedure 700 from Figure 8. Fig. 7, which is in the vehicle system 6 from Fig. 1 is implemented. Curve 810 represents a condition of the heating element that can be set between ON and OFF positions. Curve 820 represents an FS sensor filter load, and curve 822 represents a threshold FS sensor filter load. In one example, the threshold FS sensor filter load is based on the amount of FS that has accumulated on the FS sensor filter when the particulate filter in the exhaust duct is compromised (e.g., has a leak).Curve 830 represents a temperature change measured between a first 612 and a second 614 temperature sensor; curve 832 represents a lower threshold temperature change, essentially corresponding to an average temperature change measured when the particulate filter in the exhaust duct is leak-free; and curve 834 represents an upper threshold temperature change, essentially corresponding to a temperature change measured when the particulate filter in the exhaust duct is leaking. In some examples, the lower and upper threshold temperature changes can be adjusted based on engine operating parameters. For example, the lower and upper threshold temperature changes can be increased if the engine temperature is below an ambient temperature (e.g., during a cold start).The upper threshold temperature change can be 1.5 to 3 times greater than the lower threshold temperature change.

[0090] Before t1, the heating element is switched off (graph 810) and the temperature change (graph 830) is less than the lower threshold temperature change (graph 832). In particular, the threshold temperature change is essentially 0 and the FS sensor filter is not regenerated. It will be understood that when graph 830 is masked by graph 800, the temperature change is essentially 0. The FS sensor filter load (graph 820) increases towards the threshold FS sensor filter load (graph 822) as exhaust gas flows from a section of the exhaust duct downstream of a particulate filter to the FS sensor filter. At t1, the time since a previous regeneration is greater than or equal to a threshold interval. Therefore, the heating element is activated to initiate regeneration and the particulate filter load begins to decrease.Additionally, the temperature change begins to increase when the exhaust gas downstream of the filter is hotter than the exhaust gas upstream of the filter due to regeneration.

[0091] After t1 and before t2, the heating element remains active, and the FS sensor filter load begins to decrease to a relatively low level as the FS is burned off from the filter. At t2, the temperature change essentially corresponds to the lower threshold temperature change. This ensures that the particulate filter in the exhaust duct is functioning as intended and is not compromised. The 800 curve represents a larger temperature change that occurs at the end of the regeneration. However, it should be understood that the highest temperature change during regeneration can occur at any time between t1 and t2. The threshold regeneration period is complete, and the heating element is deactivated. Thus, regeneration ends when the heating element is deactivated. In some cases, regeneration may continue after the heating element is deactivated.According to this, self-combustion occurs and the FS load on the filter continues to decrease.

[0092] After t2 and before t3, the FS sensor filter load increases as exhaust gas containing FS flows through the FS sensor. At t3, the threshold interval between regenerations is reached, and the heating element is activated to regenerate the filter in the FS sensor. Consequently, a temperature difference begins to develop between the first and second temperature sensors.

[0093] After t3 and before t4, the temperature change increases to a level greater than the lower threshold temperature change when the particulate filter (PF) continues to regenerate. The PF sensor filter load continues to decrease. The heating element remains activated. At t4, the threshold regeneration period is complete. The maximum temperature change is greater than the lower threshold temperature change but less than the upper threshold temperature change. Therefore, the particulate filter in the exhaust duct upstream of the PF sensor is not affected. The heating element is deactivated.

[0094] After t4 and before t8, the FS sensor filter load begins to increase and rises to a level greater than the threshold FS sensor filter load. As described above, the threshold FS sensor filter load corresponds to a certain amount of hot FS regeneration temperature.

[0095] Accordingly, a change in the exhaust gas temperature above the filter is greater than or equal to the threshold temperature change at the next regeneration. At t5, the time elapsed since the previous regeneration essentially corresponds to the threshold interval, and regeneration is initiated. The heating element is then activated, and the particulate matter begins to burn off from the filter. The temperature change begins to increase as the exhaust gas becomes hotter downstream of the filter.

[0096] After t5 and before t6, the heating element remains switched on, and the FS sensor filter load continues to decrease. The temperature change measured across the filter exceeds the upper threshold temperature change. Therefore, the temperature change (e.g., the temperature difference between the exhaust gas downstream and upstream of the filter) is similar to 1.5 times the average temperature change (e.g., the lower threshold temperature change) measured when the particulate filter in the exhaust duct is not affected. At t6, the threshold regeneration period is fulfilled, and the heating element is deactivated. The FS sensor filter load is reduced to a relatively low level, similar to the FS load at t3. Thus, the heating element returns the FS sensor filter to a similar condition after each regeneration.

[0097] After t6, the threshold regeneration period is complete and the heating element is deactivated. The FS sensor filter load begins to increase. Additionally, the particulate filter is flagged as compromised. In one example, a warning light is activated to alert the driver to the compromise. Additionally or alternatively, the engine operating parameters are adjusted as described above to reduce the FS output from the engine.

[0098] In this way, a particulate matter sensor positioned downstream of a particulate filter can diagnose the filter's condition based on one or more factors, including friction and temperature. For example, the sensor might include a rotating screen designed to draw more power when the particulate matter deposited on the sensor's filter becomes increasingly contaminated. Additionally or alternatively, the sensor might include a pair of temperature sensors positioned upstream and downstream of the filter. The temperature difference between these two sensors will be greater during filter regeneration cycles, which involve a higher concentration of particulate matter on the filter.The technical effect of monitoring a fine dust filter via friction and / or temperature changes is to accurately monitor fine dust escaping through the fine dust filter using a compact and easy-to-manufacture fine dust sensor.

[0099] A method comprises periodically rotating a screen of a particulate matter sensor via an actuator and indicating a leakage of a particulate matter filter based on a quantity of power supplied to the actuator. A first example of the method further comprises the screen being pressed against a filter of the particulate matter sensor, the screen being periodically rotated in response to operating conditions of the engine and / or exhaust system, and the indication including setting a diagnostic code and / or providing a message or illumination to a driver via a display in a vehicle in which the sensor is mounted. A second example of the method, which optionally includes the first example, further comprises the rotation including the supply of power to the actuator to rotate the screen between 2 and 15 degrees.A third example of the procedure, which optionally includes the first and / or second example, further involves rotating at fixed intervals. A fourth example of the procedure, which optionally includes one or more of the first three examples, further involves determining the leakage based on a finding that the power output exceeds a threshold power.

[0100] One embodiment of the method comprises heating a filter of a particulate matter sensor in an engine exhaust and indicating a leakage of the particulate matter filter based on a temperature difference of the exhaust gas upstream and downstream of the filter. A first example of the method optionally includes that the particulate matter sensor is coupled to a first temperature sensor upstream of the filter and to a second temperature sensor downstream of the filter relative to a direction of the incoming exhaust gas flow. A second example of the method, which optionally includes the first example, further includes that the heating is carried out at regular intervals. A third example of the method, which optionally includes the first and / or second example, further includes that the temperature difference corresponds to 1.5 times the regeneration temperature of the filter.

[0101] One embodiment of a system comprises an exhaust duct having a particulate filter and a particulate sensor located downstream of the particulate filter relative to a direction of exhaust flow, wherein the particulate sensor is coupled to an upstream pipe, a downstream pipe, and a connecting pipe physically coupled to one another in a U-shape. A first example of the system further includes the upstream pipe having a plurality of perforations to allow exhaust gas to flow into the particulate sensor. A second example of the system, which optionally includes the first example, further includes the downstream pipe having an outlet for expelling exhaust gas into the exhaust duct. A third example of the system, which optionally includes the first and / or second example, further includes the connecting pipe being located entirely outside the exhaust duct.A fourth example of the system, which optionally includes one or more of the first three examples, further includes that the upstream and downstream pipes are perpendicular to a central axis of the exhaust duct. A fifth example of the system, which optionally includes one or more of the first four examples, further includes that the connecting pipe is parallel to the central axis. A sixth example, which optionally includes one or more of the first five examples, further includes that the particulate matter sensor is asymmetrical and that the upstream pipe extends further into the exhaust duct than the downstream pipe. A seventh example, which optionally includes one or more of the first six examples, further includes that the connecting pipe incorporates a filter designed to capture particulate matter and a heating element for heating the filter.An eighth example, which optionally includes one or more of the first through seventh examples, further includes that the heating element periodically heats the filter based on a fixed time interval, and that the connecting tube further includes a first and a second temperature sensor upstream and downstream of the filter, respectively, and that impairment of the particulate filter is determined based on a temperature difference between the first and second temperature sensors. A ninth example, which optionally includes one or more of the first through eighth examples, further includes that the connecting tube further includes a screen pressed against the filter, and that the screen is designed to rotate periodically via an actuator, and that impairment of the particulate filter is determined based on a threshold voltage consumed by the actuator to rotate the screen.A tenth example, which optionally includes one or more of the first to ninth examples, further includes that the fine dust sensor does not include any additional inlets or outlets other than the perforations arranged on the upstream pipe and the outlet arranged on the downstream pipe.

[0102] It should be noted that the exemplary control and estimation routines contained herein can be used with various engine and / or vehicle system designs. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and executed by the control system, which includes the control unit in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Thus, various illustrated actions, operations, and / or functions can be performed in the illustrated sequence or in parallel, or in some cases, omitted.Likewise, the processing sequence is not strictly necessary to achieve the features and advantages of the exemplary embodiments described here, but is provided for easier illustration and description. One or more of the illustrated actions, processes, and / or functions can be performed repeatedly, depending on the specific strategy employed. Furthermore, the described actions, processes, and / or functions can graphically represent code that is to be programmed into non-volatile memory of the computer-readable storage medium in the engine control system, whereby the described actions are executed by carrying out the instructions in a system that includes the various engine hardware components in combination with the electronic control unit.

[0103] It should be noted that Fig. 2 and Fig.Six arrows indicate where there is space for a gas flow, and the solid lines of the device walls show the points where the flow is blocked and no connection is possible due to the lack of a fluidic connection. This is caused by the device walls extending from one point to another. The walls create a separation between areas, except at openings in the wall that allow the described fluid connection.

[0104] It is understood that the interpretations and routines disclosed herein are exemplary in nature and that these specific embodiments are not to be interpreted in a limiting sense, as numerous variations are possible. For example, the aforementioned technology can be applied to V-6, I-4, I-6, V-12, 4-cylinder boxer, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0105] The following claims, in particular, describe certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims are to be understood as including one or more such elements and neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether broader, narrower, the same, or different in scope compared with the original claims, are also considered to be included in the subject matter of the present disclosure.

Claims

[1] Procedure comprising the following: Periodic rotation of a sieve (254) of a fine dust sensor (106) via an actuator (304); and Indication of a leakage of a fine dust filter (102) based on a power quantity supplied to the actuator (304). [2] Method according to claim 1, wherein the sieve (254) is pressed against a filter (256) of the fine dust sensor (106), wherein the sieve (254) is periodically rotated in response to operating conditions of an engine (10) and / or exhaust system, and wherein the display includes setting a diagnostic code and / or providing a message or illumination to a vehicle operator via a display of a vehicle in which the sensor (106) is mounted. [3] Method according to claim 1, wherein the rotation comprises supplying power to the actuator (304) to rotate the sieve (254) between 2 and 15 degrees. [4] Method according to claim 1, wherein the turning is carried out in fixed period intervals. [5] Method according to claim 1, wherein the leakage is determined on the basis that the power output exceeds the threshold power.

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