Abstract:
One embodiment is a method including providing an exhaust aftertreatment system including an adsorber, commanding rich operation wherein the adsorber is provided with increased reductant, and ending rich operation upon the first of a commanded rich operation threshold being met or a confirmed rich operation threshold being met. Other embodiments include additional methods, software, apparatuses and systems. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Description:
PRIORITY 
     The benefits and rights of priority of U.S. Patent Application No. 60/876,086 filed Dec. 20, 2006 are claimed, and that application is incorporated by reference. 
    
    
     BACKGROUND 
     Internal combustion engines including diesel engines produce a number of combustion products including particulates, hydrocarbons (“HC”), carbon monoxide (“CO”), oxides of nitrogen (“NOx”), oxides of sulfur (“SOx”), and others. Diesel engines may be required to reduce or eliminate emission of these and other products of combustion, for example, by using one or more adsorbers to store SOx and/or NOx. When an adsorber reaches a certain storage capacity it can be regenerated. The regeneration of adsorbers to eliminate stored sulfurous or sulfur-containing compounds is termed deSOx. The regeneration of adsorbers to eliminate stored nitrogenous or nitrogen-containing compounds NOx is termed deNOx. DeNOx and deSOx may require control of a variety of different operating conditions. 
     SUMMARY 
     One embodiment is a method including providing an exhaust aftertreatment system including an adsorber, commanding rich operation wherein the adsorber is provided with increased reductant, and ending rich operation upon the first of a commanded rich operation threshold being met or a confirmed rich operation threshold being met. Other embodiments include additional methods, software, apparatuses, techniques, and systems. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a schematic of an exemplary diesel engine system. 
         FIG. 2  is a schematic the exhaust aftertreatment system of the system of  FIG. 1 . 
         FIG. 3  is a diagram of an exemplary controls executable by an ECU or other processor. 
         FIG. 4  is a diagram of an exemplary aftertreatment control system. 
         FIG. 4A  is a diagram of an exemplary deSOx control module. 
         FIG. 5  is a diagram of deSOx beta timer  500  of  FIG. 4 . 
         FIG. 5A  is a diagram of deSOx beta timer  500 A of  FIG. 4A . 
         FIG. 6  is a diagram of feedforward temperature control  600  of  FIG. 4 . 
         FIG. 7  is a diagram of feedback temperature control  700  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     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, such alterations and further modifications in the illustrated embodiments, and such further applications of the principles of the embodiments illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     With reference to  FIG. 1 , there is illustrated system  10  which includes an internal combustion engine  12  operatively coupled with an exhaust aftertreatment system  14 . Exhaust aftertreatment system  14  includes a diesel oxidation catalyst unit  16  which is preferably a close coupled catalyst but could be other types of catalyst units, an adsorber, preferably a NOx adsorber, a lean NOx trap  18  or another type of adsorber, and a diesel particulate filter  20 . The exhaust aftertreatment system  14  is operable to reduce or remove unwanted emissions from exhaust gas exiting the engine  12  after combustion. 
     Diesel oxidation catalyst unit  16  is preferably a flow through device that includes a canister that includes a honey-comb like structure or substrate. The substrate has a surface area that includes a catalyst. As exhaust gas from engine  12  traverses the catalyst, CO, gaseous HC and liquid HC (e.g., unburned fuel and oil) are oxidized and can be converted to carbon dioxide and water. 
     NOx adsorber  18  is operable to adsorb NOx and SOx emitted from engine  12  to reduce their emission into the atmosphere. NOx adsorber  18  includes catalyst sites which catalyzes oxidation reactions and storage sites which store compounds. After NOx adsorber  18  reaches a certain storage capacity it may be regenerated through deNOx and/or deSOx operations. 
     Diesel particulate filter  20  may include one or more of several types of particle filters. Diesel particulate filter  20  is utilized to capture unwanted diesel particulate matter from the flow of exhaust gas exiting the engine  12 . Diesel particulate matter may include sub-micron size particles found in diesel exhaust, including both solid and liquid particles, as well as fractions such as inorganic carbon (soot), organic fraction (often referred to as SOF or VOF), and sulfate fraction (hydrated sulfuric acid). Diesel particulate filter  20  may be regenerated at regular intervals by combusting particulates collected in diesel particulate filter  20 , for example, through exhaust manipulation. 
     During engine operation, ambient air is inducted from the atmosphere and is preferably compressed by a compressor  22  of a turbocharger  23  before being supplied to the engine  12 . The compressed air is supplied to the engine  12  through an intake manifold  24  that is connected with the engine  12 . An air intake throttle valve  26  may be positioned between the compressor  22  and the engine  12  that is operable to control the amount of charge air that reaches the engine  12  from the compressor  22 . The air intake throttle valve  26  may be coupled with, and controlled by, an engine control unit (“ECU”)  28 , but may be controlled by other controllers as well. The air intake throttle valve  26  is operable to control the amount of charge air entering the intake manifold  24  via the compressor  22 . 
     An air intake sensor  30  is included either before or after the compressor  22  to monitor the amount of ambient air or charge air being supplied to the intake manifold  24 . The air intake sensor  30  may be connected with the ECU  28  and may generate electric signals indicative of the amount of charge air flow. An intake manifold pressure sensor  32  is connected with the intake manifold  24 . The intake manifold pressure sensor  32  is operative to sense the amount of air pressure in the intake manifold  24 , which is indicative of the amount of air flowing or provided to the engine  12 . The intake manifold pressure sensor  32  is connected with the ECU  28  and generates electric signals indicative of the pressure value that are sent to the ECU  28 . 
     The system  10  may also include a fuel injection system  34  such as a high pressure common rail fuel system that is connected with, and controlled by, the ECU  28 . The purpose of the fuel injection system  30  is to deliver fuel into the cylinders of the engine  12 , while precisely controlling the timing of the fuel injection, fuel atomization, the amount of fuel injected, the number and timing of injection pulses, as well as other parameters. In certain embodiments stratified injection modes may be used. In other embodiments homogeneous, partial homogeneous and/or mixed injection modes may be used. Fuel is injected into the cylinders of the engine  12  through one or more fuel injectors  36  and is combusted, preferably by compression, with charge air and/or EGR received from the intake manifold  24 . Various types of fuel injection systems may be utilized in the present invention, including, but not limited to, pump-line-nozzle injection systems, unit injector and unit pump systems, common rail fuel injection systems and others. 
     Exhaust gases produced in each cylinder during combustion exit the engine  12  through an exhaust manifold  38  connected with the engine  12 . A portion of the exhaust gas may be routed to an exhaust gas recirculation (“EGR”) system  40  and a portion of the exhaust gas is supplied to a turbine  42 . The turbocharger  23  may be a single variable geometry turbocharger  23 , but other types and/or numbers of turbochargers may be utilized as well. The EGR system  34  may be used to cool down the combustion process by providing a selectable amount of exhaust gas to the charge air being supplied by the compressor  22 . Cooling combustion may reduce the amount of NOx produced during combustion. One or more liquid, charge air, and/or other types of EGR coolers  41  may be included to further cool the exhaust gas before being supplied to the air intake manifold  22  in combination with the compressed air passing through the air intake throttle valve  26 . 
     EGR system  40  includes an EGR valve  44  in fluid communication with the outlet of the exhaust manifold  38  and the air intake manifold  24 . EGR valve  44  may also be connected to ECU  28 , which is capable of selectively opening and closing EGR valve  44 . EGR valve  44  may also have incorporated therewith a differential pressure sensor that is operable to sense a pressure change, or delta pressure, across EGR valve  44 . A pressure signal  46  may also be sent to ECU  44  indicative of the change in pressure across EGR valve  44 . An air intake throttle valve  26  and EGR system  40 , in conjunction with fuel injection system  34 , may be controlled to run engine  12  in a rich mode or in a lean mode. 
     The portion of the exhaust gas not communicated to the EGR system  40  is communicated to turbine  42  of a turbocharger, which is driven by gases flowing through the turbine  42 . Turbine  42  is connected to compressor  22  and provides driving force for compressor  22  which generates charge air supplied to the air intake manifold  24 . As exhaust gas leaves turbine  42 , it is directed to exhaust aftertreatment system  14 , where it is treated before exiting the system  10 . 
     A cooling system  48  may be connected with the engine  12 . The cooling system  48  transfers heat out of the block and other internal components of the engine  12 . to a liquid coolant. The cooling system  48  preferably includes a water pump, radiator or heat exchanger, water jacket (including coolant passages in the block and heads), and a thermostat. Thermostat  50 , which is the only component of cooling system  48  illustrated in  FIG. 1 , is connected with ECU  28 . Thermostat  50  is preferably operable to generate a signal that is sent to ECU  28  that indicates the temperature of the coolant used to cool engine  12 . 
     System  10  may include a doser  52  which may be located in the exhaust manifold  38  and/or located downstream of the exhaust manifold  38 . Doser  52  may comprise an injector mounted in an exhaust conduit  54 . In the illustrated embodiment, the reductant or reducing agent introduced through the doser  52  is diesel fuel; however, other embodiments are contemplated in which one or more different reductants are used in addition to or in lieu of diesel fuel. Additionally, reductant dosing could occur at a different location from that illustrated. Doser  52  is in fluid communication with a fuel line coupled to a source of fuel or other reductant (not shown) and is also connected with the ECU  28 , which controls operation of the doser  52 . Other embodiments omit or do not utilize a doser. For example, a preferred embodiment utilizes in-cylinder dosing where the timing and amount of fuel injected into the engine cylinders by fuel injectors is controlled in such a manner that engine  12  produces exhaust including a controlled amount of un-combusted (or incompletely combusted) fuel. Further embodiments may use a combination of in-cylinder dosing and dosing from a doser. 
     System  10  also includes a number of sensors and sensing systems for providing ECU  28  with information relating to system  10 . An engine speed sensor  56  may be included in or associated with engine  12  and is connected with ECU  28 . Engine speed sensor  56  is operable to produce an engine speed signal indicative of engine rotation speed (“RPM”) that is provided to ECU  28 . A pressure sensor  58  may be connected with the exhaust conduit  54  for measuring the pressure of the exhaust before it enters the exhaust aftertreatment system  14 . Pressure sensor  58  may be connected with ECU  28 . If pressure becomes too high, this may indicate that a problem exists with the exhaust aftertreatment system  14 , which may be communicated to ECU  28 . 
     At least one temperature sensor  60  may be connected with the diesel oxidation catalyst unit  16  for measuring the temperature of the exhaust gas as it enters the diesel oxidation catalyst unit  16 . In other embodiments, two temperature sensors may be used, one at the entrance or upstream from the diesel oxidation catalyst unit  16  and another at the exit or downstream from the diesel oxidation catalyst unit  16  or at other locations. These temperature sensors are used to calculate the temperature of the diesel oxidation catalyst unit  16 . In one embodiment, an average temperature may be determined, using an algorithm, from the two respective temperature readings of the temperature sensors  60  to arrive at an operating temperature of the diesel oxidation catalyst unit  16 . 
     Referring to  FIG. 2 , a schematic diagram of exemplary exhaust aftertreatment system  14  is depicted connected in fluid communication with the flow of exhaust leaving the engine  12 . A first NOx temperature sensor  62  may be in fluid communication with the flow of exhaust gas before entering or upstream of the NOx adsorber  18  and is connected to ECU  28 . A second NOx temperature sensor  64  may be in fluid communication with the flow of exhaust gas exiting or downstream of the NOx adsorber  18  and is also connected to ECU  28 . NOx temperature sensors  62 ,  64  are used to monitor the temperature of the flow of gas entering and exiting NOx adsorber  18  and provide electric signals to ECU  28  which are indicative of the temperature of the flow of exhaust gas. An algorithm may then be used by ECU  28  to determine the operating temperature of NOx adsorber  18 . 
     A first universal exhaust gas oxygen (“UEGO”) sensor or lambda sensor  66  may be positioned in fluid communication with the flow of exhaust gas entering or upstream from NOx adsorber  18  and a second UEGO sensor or lambda sensor  68  may be positioned in fluid communication with the flow of exhaust gas exiting or downstream of NOx adsorber  18 . Sensors  66 ,  68  are connected with ECU  28  and generate electric signals that are indicative of the amount of oxygen contained in the flow of exhaust gas. Sensors  66 ,  68  allow ECU  28  to accurately monitor air-fuel ratios (“AFR”) also over a wide range thereby allowing ECU  28  to determine a lambda value associated with the exhaust gas entering and exiting NOx adsorber  18 . 
     Referring back to  FIG. 1 , an ambient pressure sensor  72  and an ambient temperature sensor  74  may be connected with ECU  28 . Ambient pressure sensor  72  is utilized to obtain an atmospheric pressure reading that is provided to ECU  28 . As elevation increases, there are fewer and fewer air molecules. Therefore, atmospheric pressure decreases with increasing altitude at a decreasing rate. Ambient temperature sensor  74  is utilized to provide ECU  28  with a reading indicative of the outside temperature or ambient temperature. As set forth in greater detail below, when engine  12  is operating outside of calibrated ambient conditions (i.e. —above or below sea level and at ambient temperatures outside of approximately 60-80° F.) the present invention may utilize a closed-loop control module to maintain the bed temperature of NOx adsorber  18  at the preferred regeneration temperature value (e.g. —650° C.). 
     With reference to  FIG. 3 , there is illustrated a diagram of a preferred deSOx control module  400  and a combustion manager module  106  which are preferably code stored in a computer accessible medium and executable by ECU  28 . A module can include software, firmware, hardware, and combinations of these and other elements. De-SOx control module  400  can command and control regeneration of an adsorber such as NOx adsorber  18  to remove SOx that builds up on or is trapped by adsorber  18 . De-SOx control module  400  can communicate with combustion manager module  106  and with engine  12  to control aspects of engine operation, for example, the number and/or timing of fuel injection pulses, and/or amount of fuel injected in a pulse. Furthermore, engine  12  could be coupled to drive a vehicle, generator or other systems. 
     With reference to  FIG. 4 , there is illustrated a diagram of a preferred deSOx control module  400 . In general, control module  400  controls the deSOx modes of operation for a diesel engine. In a lean operating mode, relatively little unburned or partially burned fuel (or another reductant) and relatively abundant oxygen are provided to a NOx adsorber, such as NOx adsorber  18 , which operates to adsorb SOx and NOx. In rich or deSOx operating mode(s) an increased amount or relatively abundant amount of unburned or partially burned fuel (or another reductant) and relatively little oxygen are provided to a NOx adsorber which is regenerated. The preferred operation of deSOx control module  400  is further described as follows. 
     Variable  401 , the deSOx enable variable, is input to the incr condition input of deSOx delay counter  410 . When variable  401  is true, deSOx delay counter  410  will increment. When variable  401  is false, deSOx delay counter  410  will not increment. The logical inverse of variable  401  is received by the reset input of deSOx delay counter  410 . When variable  401  is true, deSOx delay counter  410  will not reset. When variable  401  is false, deSOx delay counter  410  will reset. An increment value is input to the incr value input of deSOx delay counter  410  which is used to increment counter  410  by the increment value. Variable  402 , the deSOx delay time variable, is input to the max limit input of deSOx delay counter  410  and sets the maximum limit to which deSOx delay counter  410  will increment. The output of deSOx delay counter  410  is provided to variable  420 , the deSOx delay timer variable. Conditional  425  tests if variable  420  &gt;= variable  402  and outputs the logical value of the test (true or false). The output of conditional  425  is provided to variable  430 , the deSOx delay complete variable. Thus, variable  430  is true when a specified deSOx delay period has passed, and false if a specified deSOx delay period has not passed. 
     Variable  403 , the NOx adsorber bed temperature variable, is a function of NOx adsorber catalyst/storage bed temperature. Variable  405  is a deSOx catalyst/storage bed temperature threshold variable. Conditional  445  tests if variable  403  &gt; variable  405  and outputs the logical value of the test (true or false) which is then provided to conditional  445 . Variable  401  is also provided to conditional  455  which is a Boolean AND operator. Thus, conditional  455  will output true when the NOx adsorber catalyst/storage bed temperature exceeds a threshold and deSOx is enabled. The output of conditional  455  is input to conditional  435  which is a Boolean OR operator to which variable  430  is also input. The output of conditional  435  is input to input  1  of deSOx beta timer  500 . 
     Variable  403  is input to feedforward temperature control module  600  whose first output is provided to operator  465  and whose second output is provided to input  3  of deSOx beta timer  500 . Variable  404 , the deSOx target NOx adsorber catalyst/storage bed temperature is input to variable  700  whose first output is provided to operator  465  and whose second output is provided to variable  440 . Variable  440  may be used to control timing and/or quantity of the auxiliary injection pulses (post main injection pulses) which are provided for various modes of injector operation. Operator  465  sums its inputs and provides its output to input  2  of deSOx beta timer  500 . 
     With reference to  FIG. 4A , there is illustrated a diagram of deSOx control module  400 A. In general, control module  400 A is similar to control module  400  of  FIG. 4 , however, in module  400 A variable  403  is provided to input  4  of deSOx beta timer  500 A instead of to feedforward temp control  600  as in module  400 . 
     With reference to  FIG. 5 , there is illustrated a diagram of deSOx beta timer  500  of  FIG. 4 . In general, deSOx beta timer  500  controls duration or termination of lean operation (also referred to as β 0 ) and rich operation (also referred to as β 1 ). The operation of deSOx beta timer  500  is further described as follows. 
     Variable  501  is a rich lambda threshold which defines lambda value at or below which rich operation is occurring. Variable  502  is a lambda value which is a function of the output of a sensor positioned between the outlet of a diesel oxidation catalyst and the input of a NOx adsorber, for example, UEGO or lambda sensor  66  which provides an indication of the air fuel ratio exiting the diesel. oxidation catalyst and entering the NOx adsorber. Conditional  504  tests if variable  501  &gt;= variable  502  and outputs the logical result to the input node of latching logic  508 . Thus, the input node of latching logic receives a true value when the sensed lambda value is at or below a threshold that indicates rich operation, and receives a false value otherwise. 
     Variable  503  is a lean lambda threshold which defines a value at or above which lean operation is occurring. Conditional  506  tests if variable  502  &gt;= variable  503  and outputs the logical result of the evaluation to the reset node of latch logic  508 . Thus, latching logic  508  will reset when the sensed lambda value is greater than or equal to a threshold defined for lean operation. Latching logic  508  outputs to the incr condition input of dynamic rich timer  510 . If the incr condition input receives a true input dynamic rich timer  510  increments. If the incr condition input receives a false input dynamic rich timer  510  does not increment. Thus, dynamic rich timer  510  increments only when the output of the diesel oxidation catalyst or the input to the NOx adsorber is sensed as rich. 
     Dynamic rich timer  510  receives an increment value at its incr value input, a false value at its decr condition and decr value inputs since it operates to increment, not decrement, a reset variable  507  at its reset input, and an infinite, deactivate max, or large value at its max limit input. In other embodiments, dynamic rich timer  510  could be configured to decrement. Since the termination event is controlled by the timer value exceeding a defined value and can be reset by the value of variable  507  being true, it is not necessary to control the maximum count limit. In other embodiments, dynamic rich timer could be bounded by a maximum limit. 
     The output of dynamic rich timer  510  is provided to variable  514  and to an input of conditional  518 . The RGM_DeSOx_Rich_Time variable which is output from feedforward temp control module  600  (illustrated in  FIG. 4  and in greater detail in  FIG. 6 ) is provided to the other input of conditional  518  which evaluates whether the output of dynamic rich counter  510  (or variable  514 ) &lt; the RGM_DeSOx_Rich_Time variable. Thus, conditional  518  outputs false when the deSOx time limit has not been met or exceeded and true when the deSOx time limit has been met or exceeded. The output of conditional  518  is provided to conditional  519 . 
     Variable  531 , the RGM_DeSOx_Rich_Timer variable output from duty cycle rich timer  530 , and variable  516 , the C_RGM_SXM_Tmptr_Max_Rich_Time variable which is a limit for the commanded rich time, are provided to conditional  517  which evaluates whether variable  531  &gt;=variable  516 . When the commanded rich operation time has not reached or exceeded its threshold limit, the output of conditional  517  is true. When the commanded rich operation time has reached or exceeded its threshold limit, the output of conditional  517  is false. 
     The output of conditional  517  is provided to conditional  519 . As stated above, the output of conditional  518  is also provided to conditional  519 . Conditional  519  is a Boolean OR operator. The output of conditional  519  is true if either the commanded deSOx time has reached or exceeded its maximum threshold or the dynamic rich timer has reached or exceeded its threshold. 
     The output of conditional  519  and variable  401 , the deSOx enable variable are provided to conditional  520  which is a Boolean AND operator. The output of conditional  520  is provided to the top input of switch  521 . Variable  511 , which indicates whether the deSOx dynamic rich time mode is active, and variable  512  which indicates whether oxygen sensor output is reliable or believable are provided to conditional  513  which is a Boolean AND operator. The output of conditional  513  is provided to the selection input of switch  521 . When the output of conditional  513  is true, switch  521  is in the illustrated mode where it outputs the value at its top input. When the output of conditional  513  is false, switch  521  outputs the value at its bottom input. 
     The output of switch  521  is provided to conditional  524  which is a Boolean AND operator. The logical inverse of variable  522 , the deSOx time extension variable, and the logical inverse of variable  523 , the deSOx keep hot active variable, are also provided to conditional  524 . The output of conditional  524  is provided to the control input of switch  525  and to the reset input of duty cycle lean timer  540 , the inverse of the output of conditional  524  is provided to the incr condition input of duty cycle lean timer  540 . 
     The output of switch  525  is provided to the lower input of switch  526 . Variable  527 , the deSOx beta timer override value variable, is provided to the top input of switch  526 , and variable  528 , the deSOx beta timer override variable, is provided to the control input of switch  526 . The output of switch  526  is provided to variable  529 , the deSOx beta variable, which is used to control the deSOx mode. When variable  529  is true, the mode of operation is rich operation (also referred to as β 1 ) and deSOx of the NOx adsorber occurs. When variable  529  is false, the mode of operation is lean operation (also referred to as β 0 ) SOx adsorbtion occurs in the NOx adsorber. 
     Duty cycle rich timer  530  receives variable RGM_DeSOx_Delay_Complete from input  1  to deSOx beta timer as illustrated in  FIGS. 4 and 5 . This variable is also provided to conditional  534 . This variable indicates that the deSOx delay has been competed and that deSOx is commanded. Duty cycle rich timer  530  receives an increment value at its incr value input, a false value at its decr condition and decr value inputs since it operates to increment, variable  546  at its reset input, and an infinite, deactivate max, or large value at its max limit input. In other embodiments, duty cycle rich timer  530  could be configured to decrement. Since the termination event is controlled by the timer value exceeding a defined value and can be reset by variable  546  being true, it is not necessary to control the maximum count limit. In other embodiments, dynamic rich timer could be bounded by a maximum limit. 
     The output of duty cycle rich timer  530  is provided to variable  531  and to conditional  532  which tests whether variable  531  (or the output of duty cycle rich timer  530 ) &lt; the deSOx rich time variable which is provided at input  3  to deSOx beta timer as illustrated in  FIGS. 4 and 5 . The output of conditional  532  is provided to latching logic  533  which outputs to conditional  534 . Conditional  534  is a Boolean AND operator which also receives the deSOx delay complete variable from input  1  to deSOx beta timer as illustrated in  FIGS. 4 and 5 . The output of conditional  534  is provided to switch  521 . 
     As stated above, the output of conditional  524  is provided to the reset input of duty cycle lean timer  540 , and the inverse of the output of conditional  524  is provided to the incr condition input of duty cycle lean timer  540 . The variable RGM_DeSOx_Lean_Time from input  2  to deSOx beta timer as illustrated in  FIGS. 4 and 5  is provided to the max limit input of duty cycle lean timer  540 . The output of duty cycle lean timer  540  is provided to variable  541  and conditional  542  which tests whether variable  541  (or the output of duty cycle lean timer  540 ) &gt;= the deSOx lean time variable. The output of conditional  542  is provided to operators  543  and  544  which output to latching logic  533  and operator  454  respectively. Operator  454  outputs to variable  546 . 
     With reference to  FIG. 5A , there is illustrated a diagram of deSOx beta timer  500 A of  FIG. 4A  which includes many features discussed above in connection with timer  500 . There are several differences between deSOx beta timer  500  and deSOx beta timer  500 A. In deSOx beta timer  500 A, the output of conditional  518  is provided to the input of latching logic  519 A which outputs to conditional  520 A. Conditional  520 A is a Boolean AND operator that also receives the output of conditional  577 , and the RGM_DeSOx_Rich_Time variable which is output from feedforward temp control module  600  illustrated in  FIG. 4  and in greater detail in  FIG. 6 , and outputs to switch  521 . 
     In deSOx beta timer  500 A, the output of switch  525  is provided to the bottom input of switch  590 A. Variable  588 A, the deSOx over temperature beta variable, is provided to the top input of switch  590 A. The NAC_Bed_Tmptr variable which indicates the temperature of the NOx adsorber bed and variable  587 A, the deSOx beta switch max temperature variable, are provided to conditional  589 A which tests whether variable NAC_Bed_Tmptr &gt; variable  587 . 
     In deSOx beta timer  500 A conditional  570 A receives the output of debounce  545 . Conditional  570 A is a Boolean OR operator which also receives the output of conditional  571 A, and outputs to variable  546 . 
     With reference to  FIG. 6 , there is illustrated a diagram of feedforward temp control  600 . Feedforward temp control  600  receives filtered engine speed  601  and final fueling variables  602  as inputs. These variables are provided to three dimensional lookup tables  603 ,  604  which provide their output to the illustrated switches  610  and variables. When the illustrated switches, variables and conditionals select the output of the tables, one table output is provided to the first output of feedforward temp control  600 , and the other table output is provided to the second output of feedforward temp control  600 . 
     With reference to  FIG. 7 , there is illustrated a diagram of feedback temp control  700 . Feedback temp control  700  receives filtered engine speed  721  and final fueling variables  722  as inputs. These variables are provided to three dimensional lookup tables  723 ,  724  which provide their output to the illustrated switches conditionals and variables. When the illustrated switches select the output of one table or the other, that table value is provided to second output of feedback temp control  700  which is the deSOx Aux SOI Adjust variable. 
     Feedback temp control  700  also receives the NAC_IN_Tmptr variable  701  which indicates the temperature of the input to the NOx adsorber, and the NAC_Bed_Tmptr variable  702  which indicates the temperature of the NOx adsorber bed and well as target temperature variables, an enable variable, and a factor variable. These variables are processed by the illustrated operators, switches, variables and table and provided to the first output of feedback temp control  700 . 
     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 the preferred 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.