US20060168951A1

US20060168951A1 - Regeneration management system for a work machine

Info

Publication number: US20060168951A1
Application number: US11/045,294
Authority: US
Inventors: Cornelius Opris
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2005-01-31
Filing date: 2005-01-31
Publication date: 2006-08-03
Also published as: JP2006214438A; DE102005057456A1

Abstract

A regeneration system for a work machine may include a power source configured to provide a power output. The regeneration system may also include an exhaust element including a plurality of separately regenerable filter sections. A regeneration device may be operably connected to the power source and be adapted to use at least a portion of the power output to regenerate one or more of the filter sections of the exhaust element. The regeneration system may also include a controller configured to determine an amount of the power output available for regeneration of the exhaust element. The controller may also be configured to determine a number of filter sections that may be regenerated based on the amount of the power output available for regeneration.

Description

TECHNICAL FIELD

The present disclosure is directed to regeneration of exhaust system components, and more particularly, to systems and methods for regenerating exhaust system components based on an amount of power available for regeneration.

BACKGROUND

Engines including diesel engines, gasoline engines, natural gas engines, and other engines in the art, may exhaust air pollutants. The air pollutants may be composed of gaseous and solid materials, which include particulate matter. Particulate matter may include unburned carbon particles called soot. In addition, particulate matter may also contain ash, which can be used in engine oils to reduce the acidity of the oil.
The particulate matter generated may be filtered from an exhaust stream. Various technologies may be used to filter particulate matter from an exhaust stream. One of these technologies includes the use of an exhaust element, such as a particulate filter. Particulate filters trap particles contained in the exhaust stream, so the exhaust stream is cleaner when it enters the air as compared to when it exited from the engine. There exist various types of particulate filters in the art. Some filters may include porous filter material or, alternatively, some filters may use wire meshes. The pores or the wire meshes may trap the particulate mater in the exhaust stream as the exhaust stream flows from the input to the output of the filter.
Particulate matter trapped by the filter may eventually clog the filter and reduce the operating efficiency of the engine. As the filter gets clogged, the back pressure to the engine increases. Therefore, the engine may consume more fuel to produce the same amount of power as compared to when the filter is not clogged.
These and other problems may be avoided by periodic cleaning of the filter. Various methods of cleaning filters exist in the art. One method of cleaning the filter is to heat the particulate matter to a temperature at which it combusts or vaporizes. This type of filter cleaning may also be termed as regeneration.
Various regeneration systems have been proposed to regenerate an exhaust element. Many of these systems involve raising the temperature in the exhaust element to aid in regeneration. For example, U.S. Pat. No. 6,422,001 to Sherman et al (“the '001 patent”), which issued on Jul. 23, 2002, describes a method to regenerate particulate filters by adjusting the engine parameters to increase the exhaust temperature. In this method, when the back pressure in the filter reaches a predetermined threshold, the engine speed is decreased and load on the engine is increased. This causes the temperature of the exhaust stream emanating from the engine to increase and, in response, the temperature of the filter may increase. This increase in the filter temperature purportedly aids in regenerating the filter.
While the system of the '001 patent may be used to regenerate an exhaust element, the method has several shortcomings. The system may be unable to make an efficient use of the power available for regeneration. Under some conditions, rather than the entire exhaust element, only a portion of the element may need regeneration. The system of the '001 patent, however, cannot determine the amount of power required to regenerate all or a portion of the exhaust element. Further, the system lacks a capability to determine how much power is available for regeneration and to regenerate only a portion of the exhaust element.
The present disclosure is directed to overcoming one or more of the problems associated with the prior art regeneration systems.

SUMMARY OF THE INVENTION

One aspect of the present disclosure includes a regeneration system. The regeneration system may include a power source configured to provide a power output. The regeneration system may also include an exhaust element including a plurality of separately regenerable filter sections. A regeneration device may be operably connected to the power source and be adapted to use at least a portion of the power output to regenerate one or more of the filter sections of the exhaust element. The regeneration system may also include a controller configured to determine an amount of the power output available for regeneration of the exhaust element. The controller may also be configured to determine a number of filter sections that may be regenerated based on the amount of the power output available for regeneration.
Another aspect of the present disclosure includes a method of controlling regeneration of an exhaust element. The method may include flowing exhaust through a plurality of separately regenerable filter sections of the exhaust element. The method may further include determining, based on one or more operating characteristics of a power source, an amount of power available for regeneration. The method may also include determining a number of filter sections that may be regenerated based on the amount of power available for regeneration.
Yet another aspect of the disclosure includes a work machine. The work machine may include a frame. The machine may also include an engine supported by the frame and configured to generate a power output and an exhaust stream. The work machine may further include an exhaust conduit configured to receive and carry the exhaust stream. The work machine may include a particulate trap, including a plurality of separately regenerable filter sections, operably connected to the exhaust conduit such that at least a portion of the exhaust stream flows through the particulate trap. The work machine may include a regeneration device operably connected to the particulate trap. The work machine may also include a controller configured to determine an amount of the power output available for regeneration of the exhaust element. The controller may be further configured to determine a number of filter sections that may be regenerated based on the amount of the power output available for regeneration. The controller may also be configured to initiate regeneration of the number of filter sections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial representation of a work machine according to an exemplary disclosed embodiment.
FIG. 2 is block diagram of a regeneration system according to an exemplary disclosed embodiment.
FIG. 3 is a diagrammatic illustration of an exhaust element according to an exemplary disclosed embodiment.

DETAILED DESCRIPTION

FIG. 1 provides a pictorial illustration of work machine 10. Work machine 10 may include a power source 16 for supplying power to various components on work machine 10. Power source 16 may include an engine 12, and/or a power bus 14. Engine 12 may be operably connected to an exhaust system 18.
While work machine 10 is shown as a truck, work machine 10 may include various types of machines. For example, work machine 10 may be a track type tractor, wheeled tractor, dump truck, automobile, on-highway vehicle, off-highway vehicle, skid-steer, stationary generator, or any other device that generates an exhaust stream.
Power source 16 (e.g., engine 12 or power bus 14) may include any type of power source arranged to provide power to one or more components of work machine 10. For example, power source 16 may supply drive power to one or more traction devices 20, a power take off device (not shown), electrical components, or any other appropriate type of system. In certain embodiments, power source 16 may be used to provide power for regeneration of one or more components of exhaust system 18.
Engine 12 may include a diesel engine, a gasoline engine, an electric motor, a fuel cell or any other power-producing device. Power bus 14 may be used to distribute power for various purposes including regeneration. Specifically, power bus 14 may carry electrical power from various electrical power generating devices to any device that needs power for regeneration. Power bus 14 may be made with material that may conduct electricity. Such a material may be able to transfer electric power. For example, aluminum or copper may be used to make power bus 14. While aluminum or copper may be used to construct power bus 14, other conductive materials known in the art may be used to construct power bus 14.
Exhaust system 18 may include components used to transfer exhaust produced by an engine or other device from the engine to the atmosphere. For example, exhaust system 18 may include an exhaust manifold, a particulate filter or any other filtration device, a catalytic converter or any other catalytic device, a muffler, and a tailpipe (not shown).
FIG. 2 provides a block diagram representation of regeneration system 100 according to an exemplary disclosed embodiment. Regeneration system 100 may include engine 12, power bus 14, a controller 104, a regeneration device 106 and an exhaust conduit 108. Regeneration system 100 may further include pressure sensors 110 and 112. A generator 116, auxiliary power unit (“APU”) 118, and any other power source 120 may be connected to power bus 14. Other power source 120 may include one or more batteries. Exhaust conduit 108 carries exhaust stream 122.
Exhaust conduit 108 may be used to transfer exhaust stream 122 from engine 12 to an exhaust element 114. Exhaust conduit 108 may include pipes or other components that facilitate the movement of exhaust stream 122 from engine 12 to exhaust element 114.
Exhaust element 114 may include any device (e.g., a particulate trap) that traps particulate matter carried by exhaust stream 122 generated by engine 12. Exhaust element 114 may include any type of structure suitable for trapping particulates in exhaust stream 122. In one embodiment, exhaust element 114 may include a porous ceramic structure that may be configured to trap particulate matter contained in exhaust stream 122. In another embodiment, exhaust element 114 may use a mesh configured to trap particulate matter contained in exhaust stream 122.
FIG. 3 is a diagrammatic illustration of an exhaust element according to the exemplary disclosed embodiment. Exhaust element 114 may include one or more filter sections. For example, as shown in FIG. 3, exhaust element 114 includes filter sections 202, 204 and 206. Each filter section 202, 204 and 206 may be individually regenerable or as a subgroup containing any number of filter sections. Various mechanisms may be used to regenerate each filter section individually or in a subgroup. For example, a valve assembly (not shown) may be used to selectively block exhaust stream 122 from flowing into one or more filter sections 202 or 204 or 206. Regeneration device 106 may be configured to regenerate some or all of filter sections 202, 204, and 206 from which stream 122 has been blocked. While only three filter sections 202, 204, and 206 are discussed here, it should be noted that exhaust element 114 may include any number of filters sections.
In one embodiment, each filter section may include a wire mesh to trap particulate matter carried by exhaust stream 122. The wire mesh may be made of various kinds of material. In one exemplary embodiment, the wire mesh may be made of material that conducts electricity. If the wire mesh is capable of conducting electricity, current may be passed through the mesh. Consequently, heat dissipated by the mesh due to the resistance provided by it may be used to heat the particulate matter trapped in the mesh.
Returning to FIG. 2, the time to start and stop regeneration may be based on the observed pressure drop across exhaust element 114. Pressure sensors 110 and 112 may be used to determine the pressure drop across exhaust element 114. Various types of pressure sensors known in the art may be used in regeneration system 100. For example, pressure sensors 110 and 112 may include differential pressure sensors or gage pressure sensors. Pressure sensors 110 and 112 may be placed in any desired location on work machine 10. In the exemplary embodiment, as shown in FIG. 2, pressure sensor 110 may be placed upstream, and pressure sensor 112 may be placed downstream of exhaust element 114. The difference between the pressure measured by pressure sensors 110 and 112 may be used to determine an observed pressure drop across exhaust element 114.
Regeneration device 106 may be used to regenerate exhaust element 114 and may include any type of device capable of converting power to heat sufficient for regeneration of at least a portion of exhaust element 114. For example, a heat exchanger, a burner, or a resistive element may be used as regeneration device 106. In the exemplary embodiment, one or more resistive heating elements may be included in regeneration device 106. Power provided to the resistive heating element from power bus 14 may be used to heat the element. The heat dissipated by the resistive heating element may be used for the regeneration of exhaust element 114. Specifically, heat dissipated from the resistive heating element may raise the temperature of the particulate matter accumulated in exhaust element 114 to a temperature at which the particulate matter combusts or vaporizes. For purposes of this disclosure, power includes the power used to increase the temperature of the accumulated particulate matter in exhaust element 114 and any energy capable of being converted to power for increasing the temperature of the accumulated particulate matter in exhaust element 114.
Power bus 14 may be used to supply power to regeneration device 106 for regeneration of exhaust element 114. Various electrical power sources/power storage devices may be connected to power bus 14. For example, generator 116, APU 118 or any other power source 120 (e.g. one or more batteries) may be connected to power bus 14.
Generator 116 may be connected to engine 12 and may convert mechanical energy received from engine 12 to electrical energy. The power generated by generator 116 may be supplied to power bus 14. Engine 12 may be configured to provide power output for regeneration of exhaust element 114. For example, at least a portion of the power output of engine 12, which may be related to the speed of engine 12, may be used for regeneration.
In addition or alternatively, power from APU 118 may be supplied to power bus 14 for use in regeneration. APU 18 may be a combination of a small diesel engine with a generator or a fuel cell generator. In one embodiment, APU 118 may be used to generate electrical power when engine 12 is operating at low speeds or when engine 12 is not running. Electrical power generated by APU 118 may be transferred to regeneration device 106 by power bus 14. In addition, any other power source 120 may be connected to power bus 14 in order to provide power to regeneration device 106. For example, one or more batteries may be connected to power bus 14.
Controller 104 may include devices suitable for running a software application. For example, controller 104 may include a CPU, RAM, I/O modules etc. In one embodiment, controller 104 may constitute a unit dedicated to controlling the regeneration of exhaust element 114. Alternatively, controller 104 may be integrated with and/or correspond to an electronic control unit (ECU) of work machine 10.
Controller 104 may serve to control the operations of various components of work machine 10. In one embodiment, controller 104 may be configured to control the operation of regeneration device 106. For example, controller 104 may serve to determine the time to start the regeneration process. At that time, controller 104 may enable the operation of regeneration device 106. Further, controller 104 may serve to determine the time to stop the regeneration process. At that time, controller 104 may disable the operation of regeneration device 106. Controller 104 may be configured to control the operation of regeneration device 106 with the help of one or more electronically controlled elements (not shown).
Controller 104 may be configured to determine the time to commence and the time to cease regeneration based on one or more operating conditions of the engine and one or more characteristics associated with the exhaust element. For example, the time to commence regeneration and the regeneration duration may be based on the pressure drop across exhaust element 114 or the particulate matter accumulation in exhaust element 114.
Controller 104 may be configured to initiate regeneration of exhaust element 114 when the observed pressure drop across exhaust element 114 exceeds an estimated pressure drop. It should be noted that the estimated pressure drop is the expected pressure drop that may be calculated when one or more engine operating conditions of engine 12 and one or more characteristics associated with exhaust element 114 are known. Controller 104 may be configured to receive output signals from pressure sensors 110 and 112 indicative of an observed pressure drop across exhaust element 114. The estimated pressure drop may be determined based on one or more engine operating conditions of engine 12 and one or more characteristics associated with exhaust element 114. For example, the estimated pressure drop ΔP may be obtained from the following equation: $\begin{matrix} Δ P = \frac{6 μ L Q [2 (ⅇ^{γ} + 1) + γ (ⅇ^{γ} - 1)]}{N H^{4} γ (ⅇ^{γ} - 1)} & [1] \end{matrix}$
where L=length of filter sections 202, 204 and 206, Q=volumetric flow rate of the exhaust from engine 12, N=number of filter sections, H=width of each filter section 202, 204 and 206, μ is the dynamic viscosity of the gas, and $\begin{matrix} γ = \sqrt{\frac{48 k_{0} L^{2}}{w H^{3}}} & [2] \end{matrix}$
where w is the wall thickness of filter section 202, 204 and 206, and ko is the wall permeability of filter section 202, 204 and 206. It should be noted that while equation [1] represents one method for determining the estimated pressure drop across exhaust element 114, any other suitable equation may also be used.
Controller 104 may control regeneration based on a comparison of the estimated pressure drop and the observed pressure drop across element 114. If the estimated pressure drop is less than the observed pressure drop, it may indicate that the accumulation of particulate matter in exhaust element 114 has reached such a level that additional accumulation of particulate matter will affect the performance of engine 12. Controller 104 may initiate regeneration of exhaust element 114, for example, when the estimated pressure drop, ΔP, is less than the observed pressure drop across exhaust element 114.
Controller 104 may also be configured to stop regeneration of exhaust element 114 when, for example, the estimated pressure drop exceeds the observed pressure drop across exhaust element 104. For example, when the estimated pressure drop ΔP is greater than the observed pressure drop obtained from pressure sensors 110 and 112, controller 104 may be configured to stop the regeneration of exhaust element 114.
Alternatively, controller 104 may be configured to initiate and cease regeneration of exhaust element 114 based on the particulate matter accumulated in exhaust element 114. Controller 104 may be configured to determine an estimated particulate matter accumulation level in exhaust element 114 based on one or more operating conditions of engine 12 and one or more characteristics associated with exhaust element 114. It should be noted that the estimated particulate matter accumulation level in exhaust element 114 is the expected particulate matter accumulation level that is calculated when one or more operating conditions of engine 12 and one or more characteristics associated with exhaust element 114 are known. For example, the particulate matter accumulated in exhaust element 114 during any time period (Δt) may be estimated using the following equation: $\begin{matrix} m (Δ t) = m_{0} + \int_{ξ = t_{2}}^{ξ = t_{1}} [η (ξ) \cdot C_{in} (ξ) \cdot Q (ξ) \cdot \exp (- {RR}_{0} (ξ) \cdot ξ)] ⅆ ξ & [3] \end{matrix}$
where m₀is the mass of the particulate matter present in exhaust element 114 at t=t₁, and the integration limits t₁and t₂are related to the time period Δt, η is the filtration efficiency of the exhaust element, ξ is the porosity of the filter sections in exhaust element 114, C_inis the concentration of particulate matter in the exhaust upstream of exhaust element 114, Q is the exhaust volumetric flow rate, and RR₀is the overall reaction rate of combustion in the engine. It should be noted that while equation [3] is one method for calculating the particulate matter accumulation in exhaust element 114, any other suitable equations may be used for calculating an amount of particulate matter accumulated in exhaust element 114.
Using equation [3], controller 104 may be configured to initiate regeneration of exhaust element 114 when the estimated particulate matter accumulation level, (m(Δt)), in exhaust element 114 exceeds a predetermined maximum threshold value. Controller 104 may also be configured to stop regeneration when the estimated particulate matter accumulation level in the exhaust element falls below a predetermined minimum threshold value. The maximum threshold value may correspond to a value at which the amount of particulate matter accumulated in exhaust element is such that the performance of engine 12 may be impaired. Similarly, the minimum threshold value may correspond to a value at which the amount of particulate matter accumulated in exhaust element is such that the performance of engine 12 may no longer be impaired.
In addition to determining when to initiate regeneration of element 114, controller 104 may be configured to determine the number of filter sections 202, 204, and 206 that may be regenerated based on the power available for regeneration. In order to do this, controller 104 may be configured to determine the power required to regenerate an individual filter section. Controller 104 may also be configured to determine the power available for regeneration. Based on the power available for regeneration and the power required to regenerate an individual filter section, controller 104 may be further configured to determine the number of filter sections that may be regenerated. It should be noted that while only three filter sections 202, 204, and 206 are discussed here, controller 104 may be configured to determine any number of filter sections that may be regenerated based on the power available.
Controller 104 may be configured to determine the total power required for regeneration of exhaust element 114 based on the number of filter sections to be regenerated and the amount of power required to regenerate each filter section. The power required for the regeneration of each filter section 202, 204, 206, etc. may be determined based on the mechanism used for regeneration. For example, each mechanism may have an associated regeneration temperature and the power required for regeneration may be determined based on this temperature.
Alternatively, if the mass flow rate of the exhaust from engine 12 is known, the energy required to regenerate filter sections 202, 204 and 206 may be determined by the following energy balance equation:
E _r =Q _m C _p [T _r −T _c] [4]
where E_ris the energy required for regeneration, Q_mis the mass flow rate of the exhaust, C_pis the specific heat of the particulate matter, T_ris the temperature at which regeneration occurs, and T_cis the current temperature of the filter section
Controller 104 may be configured to determine an amount of power available for regeneration of exhaust element 114 by determining a difference between an amount of power generated by power source 16 and a load on power source 16. The power generated by power source 16 may be determined based on engine operating conditions and specifications of power source 16. In one embodiment, where power source 16 includes engine 12, controller 104 may be configured to determine a maximum available horsepower for engine 12 based on a given engine speed. Controller 104 may access this data from the horsepower curve of engine 12. The horsepower curve of engine 12 predicts the horsepower generated by engine 12 for a given engine speed.
Controller 104 may be further configured to determine the load on engine 12. Several factors may combine to produce a load on the engine. For example, work implement operation, operating traction devices (to move the machine), heating/cooling systems, auxiliary systems including on-board electronics etc. may all combine to produce a load on engine 12. In one embodiment, a torque measuring device may be used to measure the load on engine 12.
Controller 104 may be configured to determine the portion of power generated by engine 12 that is used to handle the load on engine 12 at a given speed. Controller 104 may obtain this information, for example, by accessing data that shows the amount of horsepower used for a given load on engine 12. Controller 104 may determine the difference between the power generated by engine 12 and the power used to handle the load on engine 12 to determine the amount of power available from engine 12 for regeneration of exhaust element 114.
In another embodiment, the current drawn from the different power-producing devices connected to power bus 14 (e.g. APU 118, other power source 120), and their corresponding power ratings may be used to determine the amount of power available from these devices for regeneration. For example, if a battery (not shown) is connected to power bus 14, the current drawn from the battery may be observed by controller 104 to determine the power that is being generated by the battery on power bus 14. Alternatively, if APU 18 is available as a power source on power bus 14, the current drawn from APU 18 may be observed by controller 104 to determine the power being generated by APU 18 on to power bus 14. Using this information along with known power rating characteristics for each of the power-producing devices, controller 104 can determine the amount of power available from these devices for regeneration.
Controller 104 may be configured to calculate a regeneration efficiency value. The regeneration efficiency value may be based on the number of filter sections regenerated and an amount of power used for regeneration. In addition, the amount of particulate matter left in the regenerated filter sections after regeneration may also be used to determine the regeneration efficiency. For example, the amount of particulate matter accumulating in exhaust element 114 may be determined by equation [3]. The particulate matter left in exhaust element 114 after its regeneration is complete may be based on the difference between the particulate matter accumulated in exhaust element 114 and the amount of particulate matter oxidized during regeneration. The amount of particulate matter oxidized during regeneration of exhaust element 114 may be determined based on the chemical kinetics of the technology used for regeneration. For example if a resistive heating element is used as regeneration device 106, the oxidization reaction rate may be obtained by equations known in the art (e.g., the Arrhenius equation). In one embodiment, the efficiency may be expressed as: $\begin{matrix} η = \frac{S_{o}}{S_{a}} & [6] \end{matrix}$
where η is the regeneration efficiency, S_ois the amount of particulate matter oxidized during regeneration and S_ais the amount of particulate matter accumulating in exhaust element 114.
Thus, the number of filter sections regenerated, the amount of particulate matter left in the regenerated filter sections after regeneration, and the total power used for regeneration may be used to determine the regeneration efficiency.

INDUSTRIAL APPLICABILITY

The disclosed regeneration system may be adapted for use in any system that could benefit from regeneration of an exhaust element. By calculating the power available in a work machine for regeneration and regenerating some or an entire portion of the exhaust element based on the power available, the disclosed system makes efficient use of the on board power available.
Use of the disclosed regeneration system may allow a work machine to regenerate an exhaust element whenever power is available to regenerate a portion of the exhaust element. This may increase life of the exhaust element because it may be regenerated more often. For example, the system may be configured so that whenever there is sufficient power available for regeneration, at least one or more filter sections are wholly or partially regenerated. Thus, the probability of the filter being clogged is reduced. Further, the probability of the exhaust element failing due to clogging by particulate matter may be reduced.
By monitoring the regeneration efficiency, the disclosed system may ensure that the on board power is used efficiently for regeneration purposes. The system may use the regeneration efficiency value to determine the number of filter sections it would regenerate in the next regeneration cycle or the amount of on board power it would use for the next regeneration cycle. For example, if the amount of particulate matter left in the regenerated filter sections after regeneration is too high, the system may reduce the number of filter sections that would be regenerated in the next regeneration cycle or increase the amount of power used from the available on board power for regeneration in the next regeneration cycle.
By ensuring that power available for regeneration is used, the disclosed system may reduce the load on the engine due to regeneration. This is because the system will only permit regeneration if there is sufficient power already available on board for regeneration. If there is none available, rather than increasing the load on the engine to generate power for regeneration, the system instead may not permit regeneration. This feature may be especially important when the load on the engine caused by other systems is high. On the other hand, by regenerating the exhaust element with the power available for regeneration, the disclosed system will make efficient use of the surplus power available when the load on the engine is low.
It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed regeneration system without departing from the scope of the disclosure. Additionally, other embodiments of the disclosed system will be apparent to those skilled in the art from consideration of the specification. It is intended that the specification and the examples be considered exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.

Claims

1. A regeneration system, comprising:

a power source configured to provide a power output;

an exhaust element including a plurality of separately regenerable filter sections;

a regeneration device operably connected to the power source and adapted to use at least a portion of the power output to regenerate one or more of the filter sections of the exhaust element; and

a controller configured to:

determine an amount of the power output available for regeneration of the exhaust element; and

determine a number of filter sections that may be regenerated based on the amount of the power output available for regeneration.

2. The regeneration system of claim 1, wherein the controller is further configured to initiate regeneration of the number of filter sections.

3. The regeneration system of claim 2, wherein the controller is further configured to calculate a regeneration efficiency value based on the number of filter sections regenerated and an amount of power used for regeneration.

4. The regeneration system of claim 3, wherein the controller is further configured to use the regeneration efficiency value to determine a number of filter sections to be regenerated in a subsequent regeneration cycle.

5. The regeneration system of claim 3, wherein the controller is further configured to use the regeneration efficiency value to determine an amount of power to be used for regeneration in a subsequent regeneration cycle.

6. The regeneration system of claim 3, wherein calculation of the regeneration efficiency value includes estimating an amount of particulate matter entering the exhaust element and an amount of particulate matter left in the exhaust element after regeneration.

7. The regeneration system of claim 2, wherein the controller is configured to control one or more valve elements to selectively control air flow to the plurality of filter sections during regeneration of the number of filter sections.

8. The regeneration system of claim 1, wherein the exhaust system element includes particulate trap.

9. The regeneration system of claim 1, wherein the power source includes an electrical energy storage device.

10. The regeneration system of claim 1, wherein the power source includes an electrical energy generation device.

11. The regeneration system of claim 1, wherein the amount of the power output available for regeneration is determined based on a difference between the power output of the power source and a load on the power source.

12. The regeneration system of claim 1, wherein the number of filter sections that may be regenerated is determined based on an amount of power needed to regenerate a single filter section.

13. The regeneration system of claim 1, wherein the power source includes an engine that generates an exhaust stream that is supplied to the exhaust element.

14. The regeneration system of claim 1, further including:

at least one pressure sensitive component configured to provide an output indicative of an observed pressure drop across the exhaust element; and

wherein the controller is further configured to:

determine an estimated pressure drop across the exhaust element and an estimated particulate matter accumulation level in the exhaust element based on one or more operating conditions of the engine and one or more filter section characteristics; and

initiate regeneration of the number of filter sections when the estimated pressure drop is less than the observed pressure drop across the exhaust element or when the estimated particulate matter accumulation level in the exhaust element exceeds a predetermined threshold value.

15. The regeneration system of claim 14, wherein the controller is further configured to stop regeneration of the number of filter sections when the estimated pressure drop exceeds the observed pressure drop across the exhaust element or when the estimated particulate matter accumulation level in the exhaust system element falls below the predetermined threshold value.

16. A method of controlling regeneration of an exhaust element comprising:

flowing exhaust through a plurality of separately regenerable filter sections of the exhaust element;

determining, based on one or more operating characteristics of a power source, an amount of power available for regeneration; and

determining a number of the filter sections that may be regenerated based on the amount of power available for regeneration.

17. The method of claim 16, further including initiating regeneration of the number of filter sections.

18. The method of claim 16, wherein determining the amount of power available for regeneration includes determining a difference between a power output of the power source and a load on the power source.

19. The method of claim 16, wherein determining the number of filter sections that may be regenerated is further based on an amount of power needed to regenerate one of the plurality of filter sections.

20. The method of claim 16, wherein the exhaust element includes a particulate trap and the power source includes an engine that generates an exhaust stream supplied to the particulate trap, the method further including:

estimating a pressure drop across the particulate trap and an amount of particulate matter accumulated in the particulate trap based on one or more operating conditions of the engine and one or more characteristics of the particulate trap;

determining an observed pressure drop across the particulate trap; and

initiating regeneration of the number of filter sections when the estimated pressure drop is less than the observed pressure drop or the estimated amount of particulate matter accumulated in the particulate trap exceeds a predetermined threshold value.

21. The method of claim 20, further including stopping regeneration of the number of filter sections when the estimated pressure drop exceeds the observed pressure drop or the estimated amount of particulate matter accumulated in the trap is below the predetermined threshold value.

22. A work machine comprising:

a frame;

an engine supported by the frame and configured to generate a power output and an exhaust stream;

an exhaust conduit configured to receive and carry the exhaust stream;

a particulate trap, including a plurality of separately regenerable filter sections, operably connected to the exhaust conduit such that at least a portion of the exhaust stream flows through the particulate trap;

a regeneration device operably connected to the particulate trap; and

a controller configured to:

determine an amount of the power output available for regeneration of the exhaust element;

determine a number of filter sections that may be regenerated based on the amount of the power output available for regeneration; and

initiate regeneration of the number of filter sections.

23. The work machine of claim 22, wherein the amount of the power output available for regeneration is based on a difference between the power output generated by the power source and a load on the power source.

24. The work machine of claim 22, wherein the controller is configured to control operation of the regeneration device and one or more valve elements, which selectively control air flow through the exhaust element, during regeneration of the number of filter sections.

25. The work machine of claim 22, further including:

wherein the controller is further configured to:

determine an estimated pressure drop across the exhaust element and an estimated particulate matter accumulation level in the exhaust element based on one or more operating conditions of the engine and one or more filter section characteristics;

initiate regeneration of the number of filter sections when the estimated pressure drop is less than the observed pressure drop across the exhaust element or when the estimated particulate matter accumulation level in the exhaust element exceeds a predetermined threshold value; and

stop regeneration of the number of filter sections when the estimated pressure drop exceeds the observed pressure drop across the exhaust element or when the estimated particulate matter accumulation level in the exhaust system element falls below the predetermined threshold value.