US20060168945A1 - Aftertreatment for combustion engines - Google Patents

Abstract

An aftertreatment system for an engine emissions trap or adsorber having a mechanism for increasing exhaust temperature of an engine to regenerate the trap or adsorber. The mechanism may include a cylinder cutout. The cylinder cutout may be actuated various ways including a use of cylinder valve control. Cutout of a cylinder or cylinders may be rotated among the cylinders of the engine. There may be sensors on the engine and in its exhaust system connected to a processor. The processor may provide an output indicating a degree of need for regenerating the trap or adsorber. An output of the processor also may be connected to the mechanism for increasing exhaust temperature so as to effect regeneration as needed. The emissions of concern may be NOx. The engine for example may be a diesel.

Description

BACKGROUND
• The present invention pertains to internal combustion engines, and particularly to engines with aftertreatment systems. More particularly, the invention pertains to NOx reduction in the exhaust stream of an engine.
SUMMARY
• The present system may use a cylinder cutout system for regeneration of a lean NOx trap or adsorber in the exhaust of an internal combustion engine.
BRIEF DESCRIPTION OF THE DRAWING
• FIG. 1 is a top view of an engine and its various components;
• FIG. 2 is a cut-away side view of a cylinder and associated components of the engine; and
• FIG. 3 is a graph of fuel injection events revealing fuel control for the engine.
DESCRIPTION
• Diesel engines may offer a 30 to 50 percent improved fuel economy over conventional gasoline engines in automobiles, but at a potential cost of increased emissions. However, a lean NOx trap system may be used to reduce NOx emissions. NOx traps generally require periodic regeneration by raising the temperature of the exhaust stream. A related-art, full flow lean NOx trap achieves regeneration through enriched operation of the engine, an approach that has several disadvantages including a high fuel penalty
• A cylinder cutout system may be used in lieu of an enriched operation to overcome the fuel economy penalty. In a conventional gasoline engine, the intake charge may be throttled under partial load on the engine in order to control the air flow, fuel flow and power generated by the engine. In an engine employing cylinder cutout, instead of throttling to control air flow, one or more cylinders may be “cut-out” in a controlled fashion by using, for example, a variable valve actuation mechanism. This approach may reduce or eliminate pumping work losses of the engine. The cylinder cut-out approach may be applied specifically to diesel engines for potentially controlling exhaust temperature and achieving increased fuel economy.
• FIGS. 1 and 2 show asystem10 having anengine11. No turbocharger or supercharger is included in the present description for clarity of description. These Figures are not necessarily drawn to scale relative to themselves or each other. For illustrative purposes, orientation of the components of the engine may not necessarily be the same inFIGS. 1 and 2.
• InFIGS. 1 and 2,air16 may enter fromair intake18 tocylinders17 via themanifold15 andintake ports19 at appropriate times. Theair16 may enter the respective cylinder during an intake cycle as permitted by anintake valve25 to thecylinder17 while apiston21 is moving down the cylinder. Subsequently, theintake valve25 may close and apiston21 may move up in the cylinder to compress theair16 up against a head structure13 (head) that is attached to the top of theblock49 containing the cylinder17 (seeFIG. 2). Theintake valve25 and anexhaust valve26 may be situated inhead13. Withvalves25 and26 closed,head13 may cap off and seal thecylinder17 encompassing a volume between thepiston21 and thehead13. As thepiston21 moves towards its closest position to the head13 (i.e., top dead center—TDC41), the volume of theair16 may decrease and the pressure may increase dramatically with closedvalves25 and26, thereby maintaining a sealedvolume containing air16. This action may be regarded as a compression cycle. Sometime before thepiston21 reaches its closest position to thehead13, somefuel27 pumped from afuel supply57 via atube58 may be provided to be injected by an injector12, situated in thehead13, into thecylinder17 resulting in a mixture with theair16. The injector may instead be located in the intake port of the head or in the intake manifold. In some instances, a carburetor-like or other fuel entry system may be implemented in lieu of the injector.
• Manifolds15 and23 may be attached to thehead13 havingports19 and22 which connect the manifolds to theirrespective valves25 and26. Thevalves25 and26 may be round but appear oval inFIG. 1 because of their slanted orientation in thehead13 relative to the top of piston21 (as shown inFIG. 2). Alternatively,valves25 and26 may be situated in the top of the cylinder block of an engine (not shown) along with respective intake and exhaust manifolds being attached to the block.
• Theintake valve25 andexhaust valve26 may be opened and closed by the movement of lobes29 and33 oncamshafts31 and32, respectively. Althoughengine11 may have a dual overhead camshaft arrangement inFIG. 2, any other mechanical valve actuation arrangement, such as one using lifters, pushrods and rocker arms, may be implemented. Also inFIG. 2,valves25 and26 may appear slightly open with the lobes away from the valve stems. That presentation may be for illustrative purposes to indicate that valve control is not necessarily due solely to camshaft position. Valve control may be actuated by lifters, solenoids or otheractuating components43 and44 inserted in thevalve stems35 and36, which may be discontinuous, within the components, between the valves and the cams, for adjusting the lengths of the stems or disabling cam actuation of thevalves25 and26, respectively. The valves may be retained closed or open via thecomponents43 and44 despite cam movement. Other mechanisms instead ofcomponents43 and44 may be incorporated for valve control.
• Valvesprings47 and48 may be situated betweencomponents43 and44 and spring base supports51 and52.Supports51 and52 may be securedtop head13. Under conventional operation and with no actuation,springs47 and48 may keepvalves25 and26 normally closed.
• Camshafts31 and32 may be linked to acrankshaft24 for rotation by one of several ways. For examples, the camshafts may be mechanically connected to the crankshaft or the camshafts may be electronically and/or hydraulically actuated with movement in accordance with a sensed position or angle of the crankshaft. Various devices such as solenoids may be utilized to actuate the valves. Other intake and exhaust approaches, even those without valves, may be alternatively incorporated in the engine.
• When thecams31 and32 rotate, the lobes29 and33 may turn toward and push thestems35 and36 to open thevalves25 and26, respectively.Rollers45 and46 may be attached to the ends of the valve stems35 and36 to remove contact and friction between the stem ends and the cam surfaces during actuation ofvalves25 and26, respectively. Thevalves25 and26 may generally be opened and closed at different times. Thecamshafts31 and32 may rotate at about one-half the rotation rate of thecrankshaft24. Various other kinds of mechanisms, besides valves and injectors, may be utilized for bringing air and fuel to the engine and for removing exhaust gases from the engine.
• Aspiston21 approaches its closest position (TDC41) tohead13 which is highest point of a connectingrod38 from the center ofcrankshaft24, the compressed mixture ofair16 andfuel27 may ignite (due to the heat of a highly compressed mixture in a diesel engine or the spark of a plug in a gasoline engine) and expand thereby providing much pressure on thepiston21 and pushing the piston down the sealedcylinder17 and away from thehead13. Piston21 may be connected via the connectingrod38 to thecrankshaft24 that is rotated by the force of the burning mixture upon the piston. Thepiston21 being forced down by the burning and expanding mixture ofair16 andfuel27 may be regarded as a power cycle.
• As the piston approaches its farthest position from the head (i.e., bottom dead center—BDC42, which is the lowest position of the connectingrod38 relative to the center of the crankshaft), theexhaust valve26 may open and thepiston21 return back up thecylinder17 and push a burnt mixture orexhaust gas14 out of thecylinder17 through theexhaust valve26 into theexhaust manifold23 via anexhaust port22, resulting in an exhaust cycle.
• Theexhaust valve26 may close and theintake valve25 open thereby permitting thepiston21 to draw in another amount ofair16 into thecylinder17 during its next intake cycle as thepiston21 moves downcylinder17 away from thehead13.
• The sequence of intake, compression, power and exhaust cycles may repeat themselves for a givenpiston21 andcylinder17 over the next two rotations of thecrankshaft24. Each of thepistons21 of theother cylinders17 may proceed through the same process. However, each piston may have its sequence of cycles offset from the other pistons in the engine by somewhere from one-half to one-and-one-half revolutions of thecrankshaft24. Thus, in the case of the fourcylinder engine11 shown inFIG. 1, there may be one power cycle from one of thepistons21 during each half revolution of thecrankshaft24.
• Engine11 may instead have a different number of cylinders and configuration such as an in-line, “V” or opposed cylinder arrangement. The engine may be an internal combustion engine of another kind not having pistons in cylinders. An example of such engine may be a Wankel engine.
• Thepresent system10 may incorporate acylinder17 cutout mechanism tailored for regeneration of a lean NOx trap50 (i.e., NOx adsorber) inFIGS. 1 and 2. For illustrative clarity, additional components for emissions control ofsystem10 are not necessarily shown in the Figures.
• Several benefits may result from the NOx trap oradsorber50 regeneration approach of thepresent system10. Relative to a first benefit, when regeneration ofNOx trap50 is triggered, acylinder17 cutout may be employed. One ormore cylinders17 may be cutout. Cutout may be rotated among cylinders to maintain mechanical (e.g., rotational) balance and thermal balance in the engine. For instance, an engine having a cutout applied sequentially to all of the cylinders may run smoother than if a cutout is constantly applied to the same cylinder or cylinders. Also, the heat in the engine may be more evenly distributed in it with a sequenced cutout. The rotation of the cutout among the cylinders may be of various sequences, patterns or forms. Cutout may raise the load on the remainingcylinders17 ofengine11, and consequently raiseexhaust14 temperature and reduce oxygen concentration (i.e., NOx reduction). Any variable valve actuation mechanism may be employed for a regeneration-driven cylinder cutout.
• Additional control ofexhaust14 temperature, oxygen and CO/hydrocarbon concentration may be achieved by secondary post-injection offuel27 in thecylinder17, supplementary injection in theexhaust14 and/or injection duration control. Fuel injection systems may be designed to provide injection events, such as thepilot event65, pre-event66,main event67, after event68,post event69 and asecond post event70 injections, in that order of time and crankshaft position, as shown in the graph offuel27 injection rate control inFIG. 3. Themain injection event67 may be nearTDC41 and thepost injection event69 and70 may be somewhere betweenTDC41 andBDC42. Thepilot event65 injection may be useful for noise control in cold operation and low rpm of theengine11. The pre-event66,main event67 and after event68 injections may aid in injection duration control and combustion rate shaping.
• All of the combustion of the injectedfuel27 does not necessarily take place incylinder17. After-event injection68 andpost-event injections69 and70 do not necessarily contribute to the power developed byengine11, but may be used judiciously to heat theexhaust14 and use up excess oxygen. In some cases when the temperature during an expansion (power) stroke incylinder17 is very low (e.g., while under light load conditions), the post event injection fuel may go out as raw fuel and become difficult to manage. Yet, there are times when twopost event injections69 and70 may be used—one to raise the combustion and exhaust temperature early in the expansion stroke and the second to further raise the temperature later in the stroke for more effect in the downstream regeneration process. However, there may be an impact on the fuel economy of theengine11 due to the post event injections or fuel injection duration. These added fuel injection events, if utilized, may be implemented to merely tweak thecylinder17 cutout approach for theNOx adsorber50 aftertreatment, not to replace the cutout.
• Relative to a second benefit, regeneration may be triggered based on an NOx sensor orsensors54 or on a model-based calculation of NOx emissions. This calculation may be used to estimate the total NOx adsorbed since the last regeneration event and/or determine the current adsorption efficiency. Either of these results may be used to trigger regeneration and cutout.
• Relative to a third benefit,cylinder17 cutout may be used to maintain anexhaust14 operating temperature within the optimum or desired adsorption temperature window, for trapping and storing emissions, thereby extending the period over which theNOx adsorber50 can operate before needing regeneration.
• An integrated sensing and control system may be used, including a calculation module in anECU40 that determines whencylinder17 cutout is to be employed. Calculations by the module may be based on sensor readings, in particular,exhaust14 temperatures fromsensor55 andsensor56, NOx emission measurements fromsensor54, and the adsorber state as known or estimated from sensed data or calculations. Other variables such ascurrent engine11 load and speed may also be incorporated in the calculation.
• In the case where accurate NOx sensors are not available, a mathematical or NOx emissions model may be incorporated within or connected to the calculation module. This model may also be used in a predictive capacity, for forecasting future emission levels based on projected operating conditions of the engine.
• The calculation module may render acylinder17 cutout decision based on a heuristic or model-based algorithm. An example of a heuristic algorithm may be a simple rule that dictatescylinder17 cutout when the adsorber state is below a predetermined threshold. Another example may be a rule that dictatescylinder17 cutout when the adsorber state is acceptable but exhaust temperature has been too low for optimum adsorber operation for some predetermined duration. An example of a model-based algorithm may be a predictive calculation, based on current operation and sensed parameters ofengine11, indicating when the adsorber is likely to become saturated.
• A provision may be included for a higher-level mode command from the central engine computer unit (ECU40) that can override an aftertreatment-centered calculation. TheECU40 may incorporate a processor, a computer, a controller, a calculation module and/or an emissions model. The output of thecylinder17 cutout calculation may be routed to either a dedicated cylinder controller or theengine ECU40. The fuel penalty for this additional control may be much less than for that without cylinder cutout.
• If acylinder17 cutout is desired or needed, it may be actuated with the valve mechanism shown as an illustrative example. Other approaches may be implemented such asfuel27 shut off to theparticular cylinder17 involved. In the present approach, the injector12 may be turned off and additionally thevalves25 and26 may be deactivated in a closed position. However, the valves may be deactivated in a combination of various positions, for example, aclosed exhaust valve25 and anopen intake valve26. The desired combination of deactivated positions may depend on other parameters such as oil leakage into the cylinder.
• Injector12 may be controlled with a signal alongline59 fromECU40. For instance, a signal to activate or turn on injector12 may be sent byECU40 at an appropriate time when the valves are activated to result in a power stroke. In a similar manner, injector12 may be inactivated or shut off with appropriate timing.
• InFIG. 2,valves25 and26 may have either a split ortelescoping stem35 and36, respectively. The stems35 and36 may be extended or shortened as needed forcylinder17 cutout. Thedevices43 and44 may affect or control the length or movement of stems35 and36. TheECU40 may receive signals fromtemperature sensors55 and56,NOx sensor54, and crankshaft rate and/orposition sensor39.Devices43 and44 may be deactivatable or actuatable hydraulic lifters, solenoids or similar mechanisms. Control ofdevices43 and44 may be via signals alonglines61 and62, respectively, fromECU40.
• Ifcylinder17 is to be cutout, a signal fromECU40 may go alongline61 to device43 to effectively deactivatevalve25, which means that lobe29 ofcam31 may push down on the upper portion ofstem35 without lower portion ofstem35 moving down to openvalve25. Without a signal alongline61 to device43, the pushing down of the upper portion ofstem35 would result in similar downward movement of the lower portion ofstem35 thereby openingvalve25. Similarly, a signal fromECU40 may go alongline62 todevice44 to effectively deactivatevalve26, which means that lobe33 ofcam32 may push down on the upper portion ofstem36 without the lower portion ofstem36 moving down to openvalve26. Without a signal alongline62 todevice44, the pushing down of the upper portion ofstem36 would result in a similar downward movement of the lower portion ofstem36 thereby openingvalve26.
• The times of the activation and non-activation ofvalves25 and26 may be electronically controlled byECU40. Similarly, the times of activation of injector12 may be electronically controlled byECU40.Cylinder17 cutout may be achieved by a variety of patterns of activation and deactivation ofvalves25 and26, with specific timing for each of the valves' activations and deactivations. For instance, it may be possible to deactivate only one of the valves for certain durations of time. Also, the deactivation and corresponding durations of injector12 may be a part ofcylinder17 cutout. Various sorts of calculations and programs may be selected and executed byECU40, for effectingcylinder17 cutout, depending on the various inputs toECU40.
• Inputs toECU40 vialine71 fromsensor39 may include revolutions per minute (rpm) and positions at various times ofcrankshaft24 with signals online71. Temperatures of theexhaust14 before and afteradsorber50 may be detected bysensors55 and56, respectively. These pre-adsorber andpost-adsorber exhaust14 temperatures may be in the form of signals alonglines72 and73 fromsensors55 and56, respectively, toECU40. Also, asensor54, or the like, may be positioned near an exit ofadsorber50 to measure the amount of NOx in theexhaust14. A signal indicating a measurement of the NOx may go along aline74 fromsensor54 toECU40. Various other signals of operating parameters of theengine11, such as cooling system temperature, oil pressure, exhaust oxygen, mass air flow, air/fuel ratio, detonation, and the like, may be conveyed toECU40 along lines from the corresponding sensors (not necessarily shown in the Figures).
• Other inputs toECU40 may be entered from auser interface63 and other engine sensors. Such other inputs may include engine throttle control, programs for theECU40, setpoints, selection among various modes of operation of the engine and the ECU, adjustments of performance and emissions related parameters, and so forth.
• In the present specification, some of the material may be of a hypothetical or prophetic nature although stated in another manner or tense.
• Although the invention has been described with respect to at least one illustrative embodiment, many variations and modifications will become apparent to those skilled in the art upon reading the present specification. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.

Claims (63)

1-64. (canceled)

65. An aftertreatment system comprising:

an emissions trap connected to an exhaust system of a multi-cylinder internal combustion engine; and

a first mechanism connected to the engine for heating the exhaust system to a temperature sufficient to regenerate the trap; and

wherein the first mechanism comprises:

a cylinder disabling device connected to the engine;

at least one temperature sensor situated in the exhaust system; and

a control unit connected to the cylinder disabling device and the at least one temperature sensor; and

wherein cylinder disabling by the cylinder disabling device is performed among cylinders in a pattern to maintain mechanical balance in the engine.

66. The system ofclaim 65, wherein cylinder disabling by the cylinder disabling device is performed among the cylinders in a pattern to maintain a thermal balance in the engine.

67. The system ofclaim 66, further comprising a second mechanism for keeping the trap within an optimum temperature range to trap and store emissions.

68. The system ofclaim 67, further comprising an emissions sensor proximate to the trap connected to the control unit.

69. The system ofclaim 68, wherein the cylinder disabling device is for heating the exhaust system.

70. The system ofclaim 69, wherein the engine is a diesel.

71. The system ofclaim 69, wherein heating the exhaust system results in regeneration of the trap.

72. The system ofclaim 71, wherein the trap is for adsorbing NOx from an exhaust from the engine.

73. The system ofclaim 72, wherein regeneration of the trap is for removing NOx from the trap.

74. The system ofclaim 69, wherein the control unit may provide signals to the cylinder disabling device to heat the exhaust as needed to regenerate the trap.

75. The system ofclaim 74, wherein the control unit receives a temperature indication from the at least one temperature sensor and an emissions indication from the emissions sensor to determine when to provide signals to the cylinder disabling device.

76. The system ofclaim 67, wherein the cylinder disabling device is for heating the exhaust system to regenerate the trap.

77. The system ofclaim 76, wherein to regenerate the trap is for removing emissions material from the trap.

78. The system ofclaim 77, wherein the control unit may provide signals to the cylinder disabling device to heat the exhaust as needed to regenerate the trap.

79. The system ofclaim 67, wherein the control unit may provide enabling signals to the cylinder disabling device according to a mathematical model.

80. The system ofclaim 67, wherein the control unit may provide enabling signals to the cylinder disabling device according to an algorithm.

81. The system ofclaim 78, wherein the engine is a diesel.

82. The system ofclaim 81, wherein the cylinder disabling device may inactivate valves to cutout cylinders.

83. The system ofclaim 66, wherein the first mechanism comprises:

a control unit connected to a fuel injection system of the engine; and

at least one temperature sensor situated in the exhaust system connected to the control unit.

84. The system ofclaim 83, wherein the control unit may affect duration of fuel injection and injection shutoff for changing the temperature of the exhaust system.

85. An aftertreatment system comprising:

an emissions trap connected to an exhaust system of a internal combustion engine; and

a mechanism connected to the engine for keeping the trap within an optimum temperature range to trap and store emissions; and

wherein the mechanism comprises:

a cylinder disabling device connected to the engine;

at least one temperature sensor situated in the exhaust system;

a control unit connected to the cylinder disabling device and the temperature sensor; and

cylinder disabling by the cylinder disabling device is performed among the cylinders in a pattern to maintain thermal balance in the engine.

86. The system ofclaim 85, wherein cylinder disabling by the cylinder disabling device is performed among the cylinders in a pattern to maintain mechanical balance in the engine.

87. The system ofclaim 86, wherein the cylinder disabling device is for heating the exhaust system.

88. The system ofclaim 87, wherein heating the exhaust system is for maintaining the trap within the optimum temperature range.

89. The system ofclaim 87, wherein the control unit may provide signals to the cylinder disabling device for heating the exhaust as needed for maintaining the trap within the optimum temperature range.

90. The system ofclaim 89, wherein the control unit may receive a temperature indication from the at least one temperature sensor and an emissions indication from the emissions sensor to determine when to provide signals to the cylinder disabling device.

91. The system ofclaim 90, wherein the control unit may determine when to provide signals to the cylinder disabling device according to a mathematical model.

92. An aftertreatment means comprising:

means for regenerating an engine exhaust emissions trap; and

means for determining a need to regenerate the emissions trap; and

wherein the means for regenerating comprises:

a cylinder cutout mechanism connected to the means for determining a need to regenerate; and

at least one temperature sensor, situated proximate to the exhaust emissions trap, connected to the means for determining a need to regenerate; and

wherein cylinders of an engine are cut out by the cylinder cutout mechanism in a pattern to maintain a thermal balance in the engine.

93. The means ofclaim 92, wherein the means for determining a need to regenerate comprises a processor connected to the at least one temperature sensor and the cylinder cutout mechanism.

94. The means ofclaim 93, wherein cylinders are cut out by the cylinder cutout mechanism in a pattern to maintain an operational mechanical balance in the engine.

95. The means ofclaim 94, further comprising a means for maintaining an appropriate temperature of the exhaust emissions trap to trap and store emissions.

96. The means ofclaim 95, wherein the exhaust emissions trap is connected to a diesel engine.

97. The means ofclaim 96, wherein the exhaust emissions is NOx.

98. The means ofclaim 95, wherein the cylinder cutout mechanism comprises a cylinder valve disabling device connected to the means for determining a need to regenerate.

99. The means ofclaim 98, wherein:

the means for determining a need to regenerate comprises a calculation module connected to the processor; and

an emissions model connected to the calculation module.

100. The means ofclaim 98, further comprising:

an NOx sensor proximate to the exhaust emissions trap; and

wherein the NOx sensor is connected to the processor.

101. A method for regeneration of an emissions trap connected to an exhaust of an engine, comprising:

determining a time when the trap needs to be regenerated; and

regenerating the trap at the time; and

wherein:

regenerating the trap comprises increasing the temperature of the trap;

the temperature of the trap is increased by increasing the temperature of the exhaust of the engine;

the temperature of the exhaust is increased by deactivating cylinders of the engine; and

the deactivating cylinders is performed in a pattern to maintain a mechanical balance of the engine.

102. The method ofclaim 101, wherein the deactivating cylinders is performed in a pattern to maintain a thermal balance of the engine.

103. The method ofclaim 102, further comprising keeping temperature of the trap at an optimum range for trapping and storing emissions.

104. The method ofclaim 103, wherein the engine is a diesel engine.

105. The method ofclaim 103, wherein the trap is an NOx trap.

106. The method ofclaim 102, wherein the deactivating cylinders comprises deactivating valve mechanisms of the cylinders.

107. The method ofclaim 105, wherein determining a time when the trap needs to be regenerated comprises monitoring an amount of NOx in the trap.

108. The method ofclaim 105, wherein determining a time when the trap needs to be regenerated comprises calculating an amount of NOx in the trap.

109. The method ofclaim 108, wherein the calculating an amount of NOx is performed according to an emissions model.

110. The method ofclaim 108, wherein the calculating an amount of NOx is performed according to an algorithm.

111. The method ofclaim 103, adding at least one post-event injection of fuel to the engine to adjust the temperature of the exhaust.

112. A regeneration system, comprising:

an emissions material trap connected to an exhaust of an engine;

at least one temperature sensor proximate to the trap;

a controller connected to the at least one temperature sensor; and

a cylinder cutout mechanism connected to the controller; and

wherein the cylinder cutout mechanism cuts out cylinders in a pattern to maintain a thermal balance in the engine.

113. The system ofclaim 112, wherein the cylinder cutout mechanism cuts out cylinders in a pattern to maintain a mechanical balance in the engine.

114. The system ofclaim 113, wherein the engine is a diesel engine.

115. The system ofclaim 114, wherein:

the trap is for adsorbing NOx; and

the trap is regenerated with an increased temperature of the exhaust.

116. The system ofclaim 115, wherein the temperature of the exhaust is increased by the cylinder cutout mechanism.

117. The system ofclaim 116, further comprising a device for determining an amount of NOx in the trap.

118. The system ofclaim 117, wherein the amount of NOx exceeding a certain level indicates a need for regenerating the trap.

119. The system ofclaim 118 wherein the device for determining an amount of NOx in the trap is an algorithm processed by the controller.

120. The system ofclaim 118, wherein the device for determining an amount of NOx in the trap is an NOx sensor proximate to the trap and connected to the controller.

121. The system ofclaim 120, wherein the cylinder cutout mechanism comprises a cylinder valve disabler.

122. A trap temperature maintaining system comprising:

an emissions trap connected to an exhaust system of an engine; and

a heating mechanism connected to the engine for keeping the emissions trap at an appropriate temperature to trap and store emissions; and

wherein:

the heating mechanism is an engine cylinder cutout device; and

the engine cylinder cutout device cuts out cylinders in a pattern to maintain a mechanical balance in the engine.

123. The system ofclaim 122, wherein the engine cylinder cutout device cuts out cylinders in a pattern to maintain a thermal balance in the engine.

124. The system ofclaim 122, wherein the engine cylinder cutout device cuts out cylinders sequentially to maintain a mechanical balance in the engine.

125. The system ofclaim 123, wherein the engine cylinder cutout device cuts out cylinders sequentially to maintain a thermal balance in the engine.

126. The system ofclaim 122, wherein the heating mechanism at certain times heats the trap to a temperature to regenerate the trap.

Images