Patent Application
20100089042
In accordance with exemplary embodiments, the present invention relates to systems and methods for regeneration of a filter, particularly a diesel particulate filter.
Regeneration of a diesel particulate filter (DPF) requires the addition of heat for initiating and continuing burning of accumulated particulate matter soot. As the soot burns a further increase in DPF temperature occurs. This increase in temperature is particularly prevalent during the initial regeneration process of the DPF causing a spike in the DPF temperature. Unfortunately, this temperature spike may decrease life of substrate material of the DPF. Accordingly, there is a need for a system and method for the reduction of temperature spikes in the DPFs during a regeneration process of the same.
Exemplary embodiments of the present invention provide devices, systems and methods for regeneration of a filter. In one exemplary embodiment, a method for regeneration of a particulate matter filter is provided. The method includes providing a heat source for regeneration of the particulate matter filter. The heat source is disposed proximate or upstream from the particulate matter filter. The method also includes activating the heat source to generate a first temperature profile of the heat source, the first temperature profile including a first temperature average. The method further includes increasing the temperature of the heat source to generate a second temperature profile of the heat source, the second temperature profile including a second temperature average, wherein the second temperature average is greater than the first temperature average.
In another exemplary embodiment, a method for regeneration of a particulate matter filter is provided. The method includes providing a heat source for regeneration of a particulate matter filter, the heat source being disposed proximate or upstream from the particulate matter filter. The method also includes activating the heat source to generate a temperature profile of the particulate matter filter, the temperature profile being suitable for causing regeneration of the particulate matter filter. The method further includes adjusting the temperature of the heat source to maintain the temperature profile of the particulate matter filter within a predetermined range.
In yet another exemplary embodiment, a method for regeneration of a particulate matter filter is provided. The method includes: balancing a high exothermic reaction of a particulate matter filter by generating a first temperature profile with a heat source; and balancing a low exothermic reaction of the particulate matter filter by generating a second temperature profile with the heat source, wherein the first temperature profile of the heat source is lower than the second temperature profile of the heat source.
The above-described and other features and advantages of the exemplary embodiments will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.
Other objects, features, advantages and details of the exemplary embodiments appear, by way of example only, in the following detailed description of the exemplary embodiments, the detailed description referring to the drawings in which:
The present invention provides devices, systems and methods for prolonged service life of an exhaust treatment device, particularly diesel particulate filters (DPF), for an engine. This is achieved, at least in part, by maintaining the maximum temperature of the exhaust treatment device below specified temperatures during a regeneration process of the same. This restriction in temperature lowers thermal stresses to the exhaust treatment thereby increasing DPF durability and life.
These and other advantageous are achieved by monitoring and/or controlling the temperature input of heat sources used for regeneration of the exhaust treatment device. The monitoring and/or controlling of the temperature provided by the heat sources provide control of the temperature of the exhaust treatment device. In one particular exemplary embodiment, this temperature control is achieved through a multiple stage heating profile of the heat source, wherein an initial or first heating profile of the heat source is lower than a second and subsequent heating profile. In another exemplary embodiment, this temperature control is achieved by monitoring a temperature of the exhaust treatment device and adjusting the temperature input of the heat source to maintain the temperature of the exhaust treatment device within a desired range or below a maximum temperature. Through these and other exemplary embodiments, the initial spike in temperature of the exhaust treatment device, as previously discussed, remains within preferred ranges.
Referring to the exemplary embodiments shown in
Exemplary embodiments of the regeneration system 10 of the present invention are configured for providing suitable heating for various exhaust treatment devices 12. Such exhaust treatment devices may include a filtration device such as a particulate matter filter (e.g., diesel particulate filter) or otherwise. Further, exemplary embodiments of the present invention may be used in various industries utilizing stationary engines, such generators, pumps or otherwise, or industries utilizing non-stationary engines such as vehicle engines. Accordingly, it is also contemplated that the regeneration system may be used with different types of fuel burning engines, such as gasoline engines, diesel engines, hybrid engines or otherwise. In one particular exemplary embodiment, the regeneration system is utilized with a diesel particulate filter of a diesel engine.
Referring to
In one exemplary embodiment, the heat source 20 comprises an electrical heat source disposed proximate to the exhaust treatment device within a container. The electric heat source is in communication with the control unit 22 for initiating heating of the electric heat source. The electric heat source includes a heat element (not shown) located within an exhaust stream of the engine that is suitable to elevate temperatures of the exhaust treatment device 12 for causing regeneration of the same. In another exemplary embodiment, the heat source 20 comprises a diesel oxidation catalyst (DOC) 21 or the like configured for causing oxidation of a combustible fuel such as gas, diesel or otherwise that is injected or otherwise placed therein. The DOC 21 includes a catalyst wash coating comprising a precious metal configured for causing oxidation of the fuel. In this embodiment, fuel is injected into the exhaust stream where it undergoes oxidation or combustion within the DOC 21 to cause heating of the exhaust treatment device. The DOC 21 is typically disposed proximate to the exhaust treatment device. However, it is possible that the DOC 21 may be further disposed upstream from the exhaust treatment device 12 such as prior to a selective catalytic reduction (SCR) device 24, as shown in
The regeneration system further contemplates one or more sensors for determining and/or monitoring the temperature of exhaust gas flowing into and out of the heat source 20, exhaust treatment device 12 or both. Such sensors are particularly advantageous for monitoring the operation (e.g., efficiency or otherwise) of the heat source 20, monitoring the temperature of the exhaust treatment device 12 during regeneration or otherwise. Further, with real-time monitoring of the temperature, it is possible to control the heat input of the heat source 20 for further controlling the temperature of the exhaust treatment device 12 during regeneration.
For example, referring to the exemplary embodiment shown in
The heat sources 20 are configured to provide suitable patterns or profiles of heat input and temperature for the exhaust treatment device 12. For example, in one configuration the heat source 20 provides constant or steady-state heat input or temperature for the exhaust treatment device 12. In this configuration the heat input and temperature generated by the heat source 20 remains relatively constant. In another configuration the heat source 20 provides variable heat input or temperature into the exhaust treatment device 12. In this configuration, the heat generates an average temperature over the duration of the heating or heat profile. Also, the constant or steady-state heat input may also include an average temperature, which generally is the temperature of the constant or steady-state heat input.
In one particularly advantageous embodiment, the regeneration system 10 includes one or more heat input or temperature profiles forming an increase in the temperature delivery or output of the heat source 20. This stepped or increasing temperature profile is particularly advantageous for maintaining optimum operating ranges of the exhaust treatment device 12. This is because, as previously mentioned, the temperature of the exhaust treatment device 12 can dramatically increase during initial regeneration of the device. Through this increasing profile, once the burn rate of particulate matter soot begins to decrease, the temperature delivered to the heat source 20 can be increased for maintaining temperatures of the exhaust treatment device 12 within desired operating or regeneration temperature ranges ensuring complete regeneration of the device.
In a first configuration of an increasing temperature profile, the temperature of the heat source 20 is varied, over time, from a first set point or average temperature to a second set point or average temperature, wherein the second set point or average temperature is greater than the first set point or average temperature. In another example, a temperature profile is provided including a varying temperature, wherein the initial or first temperature or temperature average is lower than a subsequent or second temperature or temperature average. As should be appreciated, both of these particular examples include an initial or first temperature that is lower than a subsequent second temperature for reducing potential or maximum temperature spike of the exhaust treatment device 12 during initial burn off of the particulate matter during regeneration.
In a second configuration of an increasing temperature profile, the temperature of the exhaust treatment device 12 is maintained between a temperature minimum and a temperature maximum. This is achieved by controlling the heat input and/or temperature of the of the heat source 20. As previously mentioned, the maintaining of the temperature of the exhaust treatment device 12 within a range may be achieved through known temperature settings of the heat sources 20. Alternatively, or in addition to known temperatures, the regeneration system may also include one or more temperature sensors, as previously discussed, for monitoring the temperature of the exhaust treatment device, heat source or both. As such, the heat input and temperature of the heat source can be modified to maintain the temperature of the exhaust treatment device 12 between minimum and maximum temperatures or in a specific temperature range for regeneration.
The minimum temperature for regeneration of an exhaust treatment device varies greatly depending on many factors, such as the minimum temperature required for regeneration and the maximum temperature rating of the exhaust treatment device 12. In one configuration it is contemplated that the minimum temperature comprises about 250° C., 350° C. or more. With respect to a maximum temperature, it is contemplated that the maximum temperature of the exhaust treatment device and/or heat source comprises about 750° C. Accordingly, it is further contemplated that the regeneration system is configured to maintain the exhaust treatment device 12 within a regenerative operating range. For example, it is contemplated that during regeneration the temperature of the exhaust treatment device 12 and/or heat source 20 output temp is in the temperature range of about 250° C. to 750° C. Further, in one particular exemplary embodiment, the regeneration system 10 maintains the temperature of the exhaust treatment device 12 within a desired temperature range. Such range may comprise a 200° C. range, 100° C. range, 50° C. range, 25° C. range or less. For example, should a preferred regenerative temperature comprise 600° C. and a preferred operating range comprise 100° C. then in one configuration the regeneration system maintains the temperature of the exhaust treatment device 12 between about 550° C. to about 650° C. It should be appreciated that other configurations, e.g., minimum temperature, maximum temperature and temperature ranges may exist depending on the characteristics and heat resistance of the exhaust treatment device.
The duration time of the temperature profile(s) of the heat source 20 and/or exhaust treatment device 12 are suitable for causing substantially complete regeneration of the exhaust treatment device 12. In one configuration the temperature profile includes a predetermined time duration. For example, with respect to temperature profiles of the heat source, each profile or profiles may include a predetermined time duration calculated to cause substantially complete regeneration of the exhaust treatment device 12 given the heat input and temperatures of the heat source 20. In another configuration the time duration is based upon factors such as temperature of the exhaust treatment device 12 and/or heat source 20 output, efficiency of the heat source, amount particulate matter soot or otherwise. In this example, with respect to temperature profiles of the exhaust treatment device 12, the time duration of the heat profile may be based upon sensed or expected temperatures of the exhaust treatment device 12.
The control unit 22 of the regeneration system is configured for controlling application or delivery of heat to the exhaust treatment device 12. Accordingly, the control unit 22 may be in communication with the exhaust treatment device 12, heat sources 20, temperature sensor 26, 28, 29, injector 25 or other component of the regeneration system 10. The control unit includes suitable software and algorithms for controlling regeneration of the exhaust treatment device 12 and more particularly maintaining the temperature of the exhaust treatment device 12 within acceptable levels or ranges. The control unit 22 may comprise a stand alone unit configured for controlling only the components of the regeneration system 10, which may be in communication with one or more other control units. Alternatively, the control unit comprises a portion of a more encompassing control unit configured to control multiple systems, such as an engine control unit. The control unit may be configured to be calibrated to compensate for different configurations of heat sources, temperature sensors, exhaust treatment device or otherwise. Also, this calibration may take into account the location of the heat sources and temperature sensors with respect to the exhaust treatment device. Other calibration configurations of the control unit are possible.
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While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
