WO2015171155A1

WO2015171155A1 - Techniques for minimizing aftertreatment system exhaust flow restrictions during engine operation

Info

Publication number: WO2015171155A1
Application number: PCT/US2014/037464
Authority: WO
Inventors: John Franklin WRIGHT
Original assignee: Cummins Inc.
Priority date: 2014-05-09
Filing date: 2014-05-09
Publication date: 2015-11-12

Abstract

A system and method is disclosed that utilizes a diesel particulate filter (DPF) in an exhaust aftertreatment system only in response to certain operating conditions, reducing the total amount of exhaust flow through the particulate filter during engine operations. As a result, exhaust flow restrictions and DPF regeneration requirements are reduced and fuel efficiency is improved.

Description

TECHNIQUES FOR MINIMIZING AFTERTREATMENT SYSTEM EXHAUST FLOW RESTRICTIONS DURING ENGINE OPERATION

BACKGROUND

[0001] The technical field generally relates to internal combustion engine systems which include an aftertreatment system. Modern internal combustion engines must meet stringent emission standards that include a maximum amount of soot and nitrogen oxides (NO_x) that may be emitted. Many engines now utilize aftertreatment systems to reduce engine-out emissions to regulatory levels before release to the atmosphere. Such aftertreatment systems can include a particulate filter that removes particulates from the exhaust. As the particulates accumulate, the increased exhaust restriction increases fuel consumption. In addition, the process of regenerating the aftertreatment systems often introduces an increased emissions burden on the system, fuel consumption penalties, and operational inconvenience. Therefore aftertreatment systems have become more complex to reduce the total emissions of the engines. Therefore, a need remains for further improvements in systems, apparatus, and methods in this area.

SUMMARY

[0002] One embodiment is a unique aftertreatment system that includes at least one flowpath with a particulate filter and a second flowpath that lacks a particulate filter, or that utilizes a less restrictive filter than the particulate filter. The flowpath with the particulate filter is utilized only during transient operating conditions. Other embodiments include unique methods, systems, and apparatus to reduce regeneration requirements of a particulate filter and to utilize the particulate filter only during operating conditions which require the particulate filter to meet emissions requirements. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 is a schematic block diagram of an embodiment of an aftertreatment system having a primary flow path and a separate particulate filter flow path.

[0004] FIG. 2 is a block diagram of another embodiment flow control valve operable with the system of FIG. 1.

[0005] FIG. 3 is a schematic view of a controller that functionally executes certain operations to determine a flow path selection.

[0006] FIG. 4 is a schematic flow diagram of a procedure for determining a flow path selection.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0007] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein as would normally occur to one skilled in the art to which the invention relates are contemplated herein.

[0008] FIG. 1 depicts an exemplary system 100 that includes an exhaust system 101 that receives exhaust gas produced by an engine 102. Engine 102 of system 100 may be utilized for any application, including at least providing power to a vehicle, providing power for stationary power generation, providing power generation for a motor that powers a vehicle, providing power for a pump (e.g. an oil rig pump), and/or to provide power to any other load. Engine 102 includes an intake system (not shown) through which charge air enters and the exhaust system 101 through which exhaust gas resulting from

combustion exits. Exhaust system 101 may also include various components not shown, such an exhaust gas recirculation system, a turbocharger system, coolers, and other components connecting exhaust system 101 to the intake system. It should be appreciated that not all details of these systems that are typically present are shown.

[0009] Exhaust system 101 includes an exhaust conduit 104 having an upstream portion 104a and a downstream portion 104b. Upstream portion 104a of exhaust conduit 104 is connected to a primary exhaust flowpath 106 and a diesel particulate filter (DPF) flowpath 108 at a first connection location 118. The DPF flowpath 108, or DPF leg 108, bypasses primary exhaust flowpath 106 and includes at least a DPF 110 downstream of first connection location 118. Additional aftertreatment devices can be provided in DPF flowpath 108, such as a reductant catalyst, but are not required. The primary exhaust flowpath 106, or primary leg 106, can be provided without any particulate filter. In the illustrated embodiment, primary exhaust flowpath 106 includes an oxidation catalyst and/or flow through filter 111, although embodiments of primary flowpath 106 without one or both of the oxidation catalyst and flow through filter are contemplated. If a flow through filter 111 is provided, the flow through filter is downstream of connection location 118 and is less restrictive of exhaust flow than DPF 110 even when DPF is clean and lacks any particulate matter accumulation. Thus, primary flowpath 106 is less restrictive of exhaust flow than DPF flowpath 108 under all operating conditions.

[0010] The primary exhaust flowpath 106 and DPF flowpath 108 come together at a second connection location 120 that is downstream of DPF 110. Downstream portion 104b of exhaust conduit 104 extends from second connection location 120 and includes at least one aftertreatment component such as a reductant catalyst 112. In certain

embodiments, the reductant catalyst 112 may be a selective catalytic reductant (SCR) catalyst or a deNO_x catalyst. However, the reductant catalyst 112 may be any catalyst or combination of catalysts which utilize a reductant (e.g. urea, ammonia, hydrocarbons, alcohols, or any other reductant) to reduce the emission of nitrogen oxides (NO_x) into the environment. One example of a suitable reductant is a diesel exhaust fluid (DEF) which comprises a solution of 32.5% high purity urea and 67.5% deionized water. It shall be appreciated, however, that any suitable reductant for injection into an exhaust system may also be utilized. [0011] Downstream portion 104b of exhaust conduit 104 may include one or more other aftertreatment components not shown, such as diesel oxidation catalysts, diesel particulate filters, an ammonia oxidation catalyst, and various temperature, pressure and exhaust gas constituent sensors. DPF flowpath 108 includes DPF 110 and may also include an oxidation catalyst upstream of DPF and/or one or more other aftertreatment components downstream of DPF 110.

[0012] The system 100 further includes a first flow control valve 114 in fluid communication with primary flowpath 106 and a second flow control valve 116 in fluid communication with DPF flowpath 108, each of which is downstream of first connection location 118. The flow control valves 114, 116 control the admission of exhaust gas through the primary flowpath 106 and DPF flowpath 108, respectively. In another embodiment shown in FIG. 2, a single flow control valve 122 is provided at first connection location 118 that is movable between a first position in which flow control valve 122 blocks or restricts exhaust gas from entering primary exhaust flowpath 106 and a second position, indicated by 122', in which flow control valve 122 blocks or restricts exhaust gas from entering DPF flowpath 108.

[0013] Certain operating conditions can increase or decrease the need for management of particulate emissions with DPF 110. Transient conditions associated with the operation of engine 102, for example, result in combustion conditions that generate higher levels of particulates that require removal with DPF 110 to meet emissions requirements. Other conditions, such as steady state operating conditions, result in combustion conditions in low particulate production by engine 102 and DPF 110 is not required to meet emissions requirements. During light load or steady state operating conditions of engine 102, the flow control valve 116, or flow control valve 122, may be configured to substantially block the exhaust flow through DPF flowpath 108 to the DPF 110, since the need for particulate emissions reduction is reduced, and flow control valve 114 or flow control valve 122 is configured to allow exhaust gas to enter primary exhaust flowpath 106. During transient operations, the flow control valve 114, or flow control valve 122, may be configured to substantially block the exhaust flow to the primary exhaust flowpath 106 since the need for particulate emissions reduction with DPF is required to meet emissions requirements, and flow control valve 116 or flow control valve 122 is configured to allow exhaust gas to enter DPF flowpath 108.

[0014] In certain embodiments, the flow control valve 114, 116 may be a simple on/off type valve in fluid communication with the respective flowpath 106, 108 that controls the flow of exhaust gas therethrough depending on valve position. In other embodiments, the flow control valve 114, 116 may be a variable valve which allows continuous or discretely selectable amounts of exhaust to flow to the respective flowpath 106, 108. In another embodiment, flow control valve 122 is a two position valve that is positioned to close one of the flowpaths 106, 108 and leave the other of the flowpaths 106, 108 open to receive exhaust gas flow. In further embodiments, flow control valve 122 is positionable to allow flow simultaneously to flowpaths 106, 108 but at reduced amounts than if positioned to block one of the flowpaths 106, 108.

[0015] In certain embodiments, the system 100 further includes a controller 130 structured to perform certain operations to determine a flow control valve positioning command. In certain embodiments, the controller 130 forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware. The controller 130 may be a single device or a distributed device, and the functions of the controller 130 may be performed by hardware or software.

[0016] In certain embodiments, the controller 130 includes one or more modules structured to functionally execute the operations of the controller 130. In certain embodiments, the controller 130 includes an operating conditions module and a flow control valve position determination module. The description herein including modules emphasizes the structural independence of the aspects of the controller 130, and illustrates one grouping of operations and responsibilities of the controller 130. Other groupings that execute similar overall operations are understood within the scope of the present application. Modules may be implemented in hardware on computer readable medium, and modules may be distributed across various controller components. More specific descriptions of certain embodiments of controller operations are included in the section referencing FIG. 3.

[0017] Interpreting, as utilized herein, includes receiving values by any method known in the art, including at least receiving values from a datalink or network

communication, receiving an electronic signal (e.g. a voltage, frequency, current, or PWM signal) indicative of the value, receiving a software parameter indicative of the value, reading the value from a memory location on a computer readable medium, receiving the value as a run-time parameter by any means known in the art, and/or by receiving a value by which the interpreted parameter can be calculated, and/or by referencing a default value that is interpreted to be the parameter value.

[0018] FIG. 3 is a schematic illustration of a processing subsystem 150 including a controller 130. An exemplary embodiment of the processing subsystem 150 includes an operating conditions module 152 that interprets one or more operating conditions associated with engine 102 and/or the vehicle powered by engine 102. Operating conditions include, for example, a torque request 160 by the operator that is provided to engine 102, an actual torque 162 that is output by engine 102, a throttle/brake input 164 from an accelerator and/or brake pedal 132 of system 100, GPS data 166 from a GPS device 134 of system 100 providing the location engine 102 and the vehicle powered by engine 102, and route conditions data 168 from a route conditions sensor 138 of system 100. Inputs to operating conditions module 152 can further include, for example, an acceleration torque request, a deceleration torque request, a vehicle speed, system temperatures, emission system status, travel duration, route history, pre-determined route information, and the like.

[0019] Operating conditions module 152 is configured to output a DPF

requirement determination 172 in response to the operating conditions and various predetermined thresholds indicative of a current or anticipated transient condition that indicates whether the exhaust gas output from engine 102 should pass through primary exhaust flowpath 106 or DPF bypass 108 with DPF filter 110. A positive DPF

requirement determination 172 indicates a transient condition or other operating event is presently occurring or will occur that requires or is likely to require DPF filter 110 to meet emissions requirement. A negative DPF requirement determination 172 indicates operating conditions that do not require DPF filter 110 to meet emissions requirements. As a result, exhaust gas can flow through primary exhaust flowpath 106 and operation of engine 102 under exhaust flow restrictions caused by DPF 110 is minimized, reducing fuel consumption and the accumulation of particulates on DPF 110 over time. [0020] In one embodiment, the DPF requirement determination 172 is interpreted in response to a differential between actual torque 162 and torque request 160 and a comparison of the differential to a torque differential threshold 174. The torque request 160 can be determined, for example, by a throttle command from the operator of the vehicle, by an input controller 130, or by any other suitable torque request determination. The actual torque 162 can be determined, for example, from an engine speed and fuelling amount, by one or more sensors, or by any suitable torque output determination. The torque differential threshold 174 is a predetermined limit or range of a torque differential amount that indicates a transient response by engine 102 is required that produces particulates and smoke. When the torque differential threshold 174 is exceeded by the differential between actual torque 62 and torque request 160, the DPF requirement determination 172 is positive and flow control valve position determination module 154 determines a flow control valve position command 170 in response to the current flow control valve position 180 and the DPF requirement determination 172 that routes exhaust flow through DPF flowpath 108. When the torque differential threshold 174 and the other thresholds 176, 178 are not exceeded, the DPF requirement determination 172 is negative and flow control valve position determination module 154 determines a flow control valve position command 170 in response to the current flow control valve position 180 and the DPF requirement determination 172 that routes exhaust flow through primary exhaust flow path 106.

[0021] In another embodiment, the DPF requirement determination 172 is interpreted in response to the throttle/brake input 164 and a comparison of it to an acceleration/deceleration threshold 176. The throttle/brake input 164 can be determined, for example, by a position, pressure, or other input to the accelerator and/or brake pedal 132 of the vehicle requiring a transient response by engine 102 that increases production of particulates and/or smoke. A large or sudden increase in the accelerator or brake pedal position can indicate an acceleration/deceleration amount that exceeds

acceleration/deceleration threshold 176. When the acceleration/deceleration threshold 176 is exceeded, the DPF requirement determination 172 is positive, and flow control valve position determination module 154 determines a flow control valve position command 170 in response to the current flow control valve position 180 and the DPF requirement determination 172 that routes exhaust flow through DPF flowpath 108. When the acceleration/deceleration threshold 176 and the other thresholds 174, 178 are not exceeded, the DPF requirement determination 172 is negative and flow control valve position determination module 154 determines a flow control valve position command 170 in response to the current flow control valve position 180 and the DPF requirement determination 172 that routes exhaust flow through primary exhaust flow path 106.

[0022] In another embodiment, the DPF requirement determination 172 is interpreted in response to the GPS data 166 from GPS device 134 and/or route conditions data 168 from route condition sensor 138 to determine an anticipated torque change, and a comparison of the anticipated torque change with an anticipated torque change threshold 178. The GPS data 166 can, for example, provide an indication of an upcoming grade change, an upcoming steep incline, an upcoming steep decline, or other route location data indicating an upcoming or anticipated terrain or location condition that will require a transient response from engine 102, causing a torque change in engine 102 that produces increased particulates and/or smoke. Route conditions data 168 can, for example, provide an indication of upcoming route conditions that require a transient response from engine 102, such as traffic conditions, an upcoming obstacle such as a slow moving vehicle, weather conditions, and other route condition data indicating an upcoming or anticipated route condition that will require a transient response from engine 102, causing a torque change in engine 102 the produces increased particulates and/or smoke.

[0023] When the anticipated torque change threshold 178 is exceeded by the anticipated torque change determined from the GPS data 166 and/or route condition data 168, the DPF requirement determination 172 is positive and flow control valve position determination module 154 determines a flow control valve position command 170 in response to the current flow control valve position 180 and the DPF requirement determination 172 that routes exhaust flow through DPF flowpath 108. When the anticipated torque change threshold 178 and the other thresholds 174, 176 are not exceeded, the DPF requirement determination 172 is negative and flow control valve position determination module 154 determines a flow control valve position command 170 in response to the current flow control valve position 180 and the DPF requirement determination 172 that routes exhaust flow through primary exhaust flow path 106.

[0024] An exemplary processing subsystem 150 includes one or more of torque differential threshold 174, acceleration/deceleration threshold 176, and anticipated torque change threshold 178 as set values, tabulated values, or mapped values at predetermined engine operating conditions which are calibrated and stored on the processing subsystem 150. The respective thresholds may be calibrated over any desired set of operating conditions, including without limitation operating conditions over which the engine 102 is expected to operate, operating conditions over which the engine 102 is regulated, a subset of any desired operating conditions, and/or operating conditions that are a superset of any desired operating conditions. The range and resolution of the values in the thresholds are selectable and define the resulting precision of the lookup table or other correlation. An exemplary processing subsystem 150 determines a transient condition when one or more of torque differential threshold 174, acceleration/deceleration threshold 176, and anticipated torque change threshold 178 is exceeded.

[0025] The schematic flow diagram in FIG. 4 and related description which follows provides an illustrative embodiment of performing procedures for determining a flow imbalance value. Operations illustrated are understood to be exemplary only, and operations may be combined or divided, and added or removed, as well as re-ordered in whole or part, unless stated explicitly to the contrary herein. Certain operations illustrated may be implemented by a computer executing a computer program product on a computer readable medium, where the computer program product comprises instructions causing the computer to execute one or more of the operations, or to issue commands to other devices to execute one or more of the operations.

[0026] With reference to FIG. 4, there is illustrated a flow diagram of an exemplary procedure 200 for determining a flow control valve position. The procedure 200 begins at operation 202 in which engine 102 is operated to produce an exhaust gas flow into the exhaust system 101. Procedure 200 continues at operation 204 in which controller 130 receives operating parameters of engine 102 indicative of a current or anticipated transient condition of operation for engine 102. Example operating parameters that can be received are discussed above and include a torque differential between a torque request and an output torque of the engine 102, an acceleration request or a deceleration request to an accelerator pedal, throttle, and/or brake pedal, and/or location data and route condition data.

[0027] From operation 204, procedure 200 proceeds at operation 206 to interpret the operating parameters in response to one or more of a torque differential threshold, an acceleration/deceleration threshold and/or an anticipated torque change threshold.

Procedure 200 continues at conditional 206 where it is determined whether DPF treatment of the exhaust gas flow is required due to the interpretation of the operating parameters indicating a current or anticipated transient condition. In response to conditional 206 having a NO or negative output, procedure 200 continues at operation 210 to direct the exhaust flow to primary exhaust flowpath 106 that lacks a DPF. In response to conditional 206 having a YES or positive output, procedure 200 continues at operation 212 to direct the exhaust flow to DPF flowpath 108 that includes DPF 110. Procedure 200 then returns to operation 204 to continue receiving operating parameters to monitor and determine which of the flowpaths 106, 108 to direct exhaust flow until the operation of engine 102 is terminated.

[0028] As is evident from the figures and text presented above, a variety of aspects of the present disclosure are contemplated. According to one aspect, an apparatus includes a controller structured to receive operating parameters from associated with operation of an engine connected to an aftertreatment system. The aftertreatment system includes an exhaust conduit defining an exhaust flowpath with a primary exhaust flowpath and a separate DPF flowpath, and at least one flow control valve operable to selectively open and close the primary exhaust flowpath and the DPF flowpath. The controller is operably connected to the at least one flow control valve and includes an operating conditions module configured to interpret the operating parameters associated with the engine and determine a DPF requirement in response to the operating parameters. The controller also includes a flow control valve position determination module configured to determine a flow control valve position command in response to the DPF requirement determination and a current position of the flow control valve to selectively direct exhaust flow to one of the primary exhaust fiowpath and the DPF fiowpath.

[0029] In one embodiment, the operating parameters include at least one of a torque differential between a torque request to the engine and a current torque output of the engine, position data of at least one of an accelerator pedal and a brake pedal, location data from a GPS device, and route condition data from a route condition sensor. In a refinement of this embodiment, the operating conditions module is configured to determine the DPF requirement is positive in response to at least one of the torque differential exceeding a torque differential threshold, the position data of at least one of the accelerator pedal and the brake pedal indicating an acceleration/deceleration amount exceeding an acceleration/deceleration threshold, and at least one of the location data and the route condition data indicating an anticipated torque change exceeding an anticipated torque change threshold. In response to the DPF requirement being positive, the flow control valve position determination module is configured to position the flow control valve to block the primary exhaust fiowpath and direct exhaust flow to the DPF fiowpath.

[0030] In another embodiment, the at least one flow control valve includes a first flow control valve in the primary exhaust fiowpath and a second flow control valve in the DPF fiowpath. In a further embodiment, the at least one flow control valve includes a two- way flow control valve at a connection location of the DPF fiowpath with the primary exhaust fiowpath.

[0031] According to another aspect, a system includes a diesel engine having an exhaust system including an exhaust aftertreatment system. The exhaust system includes a primary exhaust fiowpath and a DPF fiowpath, and the DPF fiowpath includes at least a DPF and the primary exhaust fiowpath lacks a DPF. The DPF fiowpath is connected to the primary exhaust fiowpath at an upstream location from the DPF and at a downstream location from the DPF and the primary exhaust fiowpath bypasses the DPF. The aftertreatment system includes a reductant catalyst downstream of the downstream location. At least one flow control valve is operable to selectively allow exhaust flow to one of the primary exhaust fiowpath and the DPF fiowpath while blocking exhaust flow to the other of the primary exhaust fiowpath and the DPF fiowpath. The system includes a controller operably connected to the at least one control valve. The controller is configured to interpret a DPF requirement in response to a transient condition of operation of the diesel engine, and in response to the DPF requirement being positive, operate the at least one flow control valve so that the exhaust flow is directed to the DPF fiowpath and blocked from the primary exhaust fiowpath, and in response to the DPF requirement being negative, operate the at least one flow control valve so that the exhaust flow is directed to the primary exhaust fiowpath and blocked from the DPF fiowpath.

[0032] In one embodiment, the at least one flow control valve includes a first flow control valve in the primary exhaust fiowpath and a second flow control valve in the DPF fiowpath. In another embodiment, the at least one flow control valve includes a two-way flow control valve at the first connection location that closes the DPF fiowpath in a first position and closes the primary exhaust flowpath in a second position. In yet another embodiment, the primary exhaust flowpath includes a flow through filter between the upstream location and the downstream location, and the flow through filter being less restrictive of exhaust flow than the DPF when the DPF has no particulate accumulation.

[0033] In another embodiment, the controller is configured to interpret the DPF requirement as positive in response to a torque differential between a torque request to the engine and an actual torque of the engine exceeding a torque differential threshold indicative of the transient condition. In yet another embodiment, the controller is configured to interpret the DPF requirement as positive in response to a position of at least one of an accelerator pedal and a brake pedal indicating an acceleration or deceleration request exceeding an acceleration/deceleration threshold indicative of the transient condition. In another embodiment, the controller is configured to interpret the DPF requirement as positive in response to at least one of a location condition and a route condition indicating an anticipated torque change in operation of the engine exceeding an anticipated torque change threshold indicative of the transient condition.

[0034] According to another aspect, a method includes: interpreting a DPF requirement from one or more operating parameters of a diesel engine indicative of a transient condition of operation of the diesel engine; in response to the DPF requirement being negative to indicate a non- transient condition, directing exhaust flow from the diesel engine through a primary exhaust flowpath that lacks a DPF; and in response to the DPF requirement being positive to indicate a transient condition, directing exhaust flow from the diesel engine through a DPF flowpath that includes a DPF for removing particulates from the exhaust flow. [0035] In one embodiment, the primary exhaust flowpath includes a flow through filter that is less restrictive of exhaust flow therethrough than the DPF when the DPF has no particulate accumulation. In another embodiment, interpreting the DPF requirement from the one or more operating parameters of the diesel engine includes comparing a torque differential between a torque request to the diesel engine and an output torque of the diesel engine to a torque differential threshold indicative of the transient condition. In yet another embodiment, interpreting the DPF requirement from the one or more operating parameters of the diesel engine includes comparing at least one of an acceleration request and a deceleration request to an acceleration/deceleration threshold indicative of the transient condition. In a further embodiment, interpreting the DPF requirement from the one or more operating parameters of the diesel engine includes determining an anticipated torque change from at least one of location data and route condition data and comparing the anticipated torque change to an anticipated torque change threshold indicative of the transient condition.

[0036] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as "a," "an," "at least one," or "at least one portion" are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language "at least a portion" and/or "a portion" is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims

WHAT IS CLAIMED IS:

1. An apparatus, comprising:

a controller structured to receive operating parameters from associated with operation of an engine connected to an aftertreatment system, the aftertreatment system including an exhaust conduit, the exhaust conduit defining an exhaust flowpath with a primary exhaust flowpath and a separate diesel particulate filter (DPF) flowpath, and at least one flow control valve operable to selectively open and close the primary exhaust flowpath and the DPF flowpath, wherein the controller is operably connected to the at least one flow control valve and includes:

an operating conditions module configured to interpret the operating parameters associated with the engine and determine a DPF requirement in response to the operating parameters; and

a flow control valve position determination module configured to determine a flow control valve position command in response to the DPF requirement determination and a current position of the flow control valve to selectively direct exhaust flow to one of the primary exhaust flowpath and the DPF flowpath.

2. The apparatus of claim 1, wherein the operating parameters include at least one of a torque differential between a torque request to the engine and a current torque output of the engine, position data of at least one of an accelerator pedal and a brake pedal, location data from a GPS device, and route condition data from a route condition sensor.

3. The apparatus of claim 2, wherein the operating conditions module is configured to determine the DPF requirement is positive in response to at least one of:

the torque differential exceeding a torque differential threshold;

the position data of at least one of the accelerator pedal and the brake pedal indicating an acceleration/deceleration amount exceeding an

acceleration/deceleration threshold;

at least one of the location data and the route condition data indicating an anticipated torque change exceeding an anticipated torque change threshold; and in response to the DPF requirement being positive, the flow control valve position determination module is configured to position the flow control valve to block the primary exhaust flowpath and direct exhaust flow to the DPF fiowpath.

4. The apparatus of claim 1, wherein the at least one flow control valve includes a first flow control valve in the primary exhaust flowpath and a second flow control valve in the DPF flowpath.

5. The apparatus of claim 1, wherein the at least one flow control valve includes a two-way flow control valve at a connection location of the DPF flowpath with the primary exhaust flowpath.

6. A system, comprising: a diesel engine having an exhaust system including an exhaust aftertreatment system;

wherein the exhaust system includes a primary exhaust flowpath and a diesel particulate filter (DPF) flowpath;

wherein the DPF flowpath includes at least a DPF and the primary exhaust flowpath lacks a DPF;

wherein the DPF flowpath is connected to the primary exhaust flowpath at an upstream location from the DPF and at a downstream location from the DPF, and the primary exhaust flowpath bypasses the DPF;

wherein the aftertreatment system includes a reductant catalyst downstream of the downstream location;

at least one flow control valve operable to selectively allow exhaust flow to one of the primary exhaust flowpath and the DPF flowpath while blocking exhaust flow to the other of the primary exhaust flowpath and the DPF flowpath; and

a controller operably connected to the at least one control valve, the controller being configured to interpret a DPF requirement in response to a transient condition of operation of the diesel engine, and in response to the DPF requirement being positive, operate the at least one flow control valve so that the exhaust flow is directed to the DPF flowpath and blocked from the primary exhaust flowpath, and in response to the DPF requirement being negative, operate the at least one flow control valve so that the exhaust flow is directed to the primary exhaust flowpath and blocked from the DPF flowpath.

7. The system of claim 6, wherein the at least one flow control valve includes a first flow control valve in the primary exhaust fiowpath and a second flow control valve in the DPF fiowpath.

8. The system of claim 6, wherein the at least one flow control valve includes a two-way flow control valve at the first connection location that closes the DPF fiowpath in a first position and closes the primary exhaust fiowpath in a second position.

9. The system of claim 6, wherein the primary exhaust fiowpath includes a flow through filter between the upstream location and the downstream location, the flow through filter being less restrictive of exhaust flow than the DPF when the DPF has no particulate accumulation.

10. The system of claim 6, wherein the controller is configured to interpret the DPF requirement as positive in response to a torque differential between a torque request to the engine and an actual torque of the engine exceeding a torque differential threshold indicative of the transient condition.

11. The system of claim 6, wherein the controller is configured to interpret the DPF requirement as positive in response to a position of at least one of an accelerator pedal and a brake pedal indicating an acceleration or deceleration request exceeding an acceleration/deceleration threshold indicative of the transient condition.

12. The system of claim 6, wherein the controller is configured to interpret the DPF requirement as positive in response to at least one of a location condition and a route condition indicating an anticipated torque change in operation of the engine exceeding an anticipated torque change threshold indicative of the transient condition.

13. A method, comprising:

interpreting a diesel particulate filter (DPF) requirement from one or more operating parameters of a diesel engine indicative of a transient condition of operation of the diesel engine;

in response to the DPF requirement being negative to indicate a non- transient condition, directing exhaust flow from the diesel engine through a primary exhaust flowpath that lacks a DPF; and

in response to the DPF requirement being positive to indicate a transient condition, directing exhaust flow from the diesel engine through a DPF flowpath that includes a DPF for removing particulates from the exhaust flow.

14. The method of claim 13, wherein the primary exhaust flowpath includes a flow through filter that is less restrictive of exhaust flow therethrough than the DPF when the DPF has no particulate accumulation.

15. The method of claim 13, wherein interpreting the DPF requirement from the one or more operating parameters of the diesel engine includes comparing a torque differential between a torque request to the diesel engine and an output torque of the diesel engine to a torque differential threshold indicative of the transient condition.

16. The method of claim 13, wherein interpreting the DPF requirement from the one or more operating parameters of the diesel engine includes comparing at least one of an acceleration request and a deceleration request to an acceleration/deceleration threshold indicative of the transient condition.

17. The method of claim 13, wherein interpreting the DPF requirement from the one or more operating parameters of the diesel engine includes determining an anticipated torque change from at least one of location data and route condition data and comparing the anticipated torque change to an anticipated torque change threshold indicative of the transient condition.